gui: Round down in devices completion (consistent with folders)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4325

cmd/stcli/cmd_folders.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/AudriusButkevicius/cli"
 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func init() {
@@ -102,8 +103,10 @@ func foldersList(c *cli.Context) {
 		if !first {
 			fmt.Fprintln(writer)
 		}
+		fs := folder.Filesystem()
 		fmt.Fprintln(writer, "ID:\t", folder.ID, "\t")
-		fmt.Fprintln(writer, "Path:\t", folder.RawPath, "\t(directory)")
+		fmt.Fprintln(writer, "Path:\t", fs.URI(), "\t(directory)")
+		fmt.Fprintln(writer, "Path type:\t", fs.Type(), "\t(directory-type)")
 		fmt.Fprintln(writer, "Folder type:\t", folder.Type, "\t(type)")
 		fmt.Fprintln(writer, "Ignore permissions:\t", folder.IgnorePerms, "\t(permissions)")
 		fmt.Fprintln(writer, "Rescan interval in seconds:\t", folder.RescanIntervalS, "\t(rescan)")
@@ -124,8 +127,9 @@ func foldersAdd(c *cli.Context) {
 	abs, err := filepath.Abs(c.Args()[1])
 	die(err)
 	folder := config.FolderConfiguration{
-		ID:      c.Args()[0],
-		RawPath: filepath.Clean(abs),
+		ID:             c.Args()[0],
+		Path:           filepath.Clean(abs),
+		FilesystemType: fs.FilesystemTypeBasic,
 	}
 	cfg.Folders = append(cfg.Folders, folder)
 	setConfig(c, cfg)
@@ -185,7 +189,9 @@ func foldersGet(c *cli.Context) {
 		}
 		switch arg {
 		case "directory":
-			fmt.Println(folder.RawPath)
+			fmt.Println(folder.Filesystem().URI())
+		case "directory-type":
+			fmt.Println(folder.Filesystem().Type())
 		case "type":
 			fmt.Println(folder.Type)
 		case "permissions":
@@ -197,7 +203,7 @@ func foldersGet(c *cli.Context) {
 				fmt.Println(folder.Versioning.Type)
 			}
 		default:
-			die("Invalid property: " + c.Args()[1] + "\nAvailable properties: directory, type, permissions, versioning, versioning-<key>")
+			die("Invalid property: " + c.Args()[1] + "\nAvailable properties: directory, directory-type, type, permissions, versioning, versioning-<key>")
 		}
 		return
 	}
@@ -220,7 +226,11 @@ func foldersSet(c *cli.Context) {
 		}
 		switch arg {
 		case "directory":
-			cfg.Folders[i].RawPath = val
+			cfg.Folders[i].Path = val
+		case "directory-type":
+			var fsType fs.FilesystemType
+			fsType.UnmarshalText([]byte(val))
+			cfg.Folders[i].FilesystemType = fsType
 		case "type":
 			var t config.FolderType
 			if err := t.UnmarshalText([]byte(val)); err != nil {

cmd/stindex/util.go

@@ -12,7 +12,7 @@ import (
 	"path/filepath"
 	"runtime"
 
-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func nulString(bs []byte) string {
@@ -33,7 +33,7 @@ func defaultConfigDir() string {
 		return filepath.Join(os.Getenv("AppData"), "Syncthing")
 
 	case "darwin":
-		dir, err := osutil.ExpandTilde("~/Library/Application Support/Syncthing")
+		dir, err := fs.ExpandTilde("~/Library/Application Support/Syncthing")
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -43,7 +43,7 @@ func defaultConfigDir() string {
 		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
 			return filepath.Join(xdgCfg, "syncthing")
 		}
-		dir, err := osutil.ExpandTilde("~/.config/syncthing")
+		dir, err := fs.ExpandTilde("~/.config/syncthing")
 		if err != nil {
 			log.Fatal(err)
 		}

cmd/syncthing/gui.go

@@ -28,9 +28,9 @@ import (
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
-	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/stats"
@@ -856,7 +856,7 @@ func (s *apiService) getSystemStatus(w http.ResponseWriter, r *http.Request) {
 	var m runtime.MemStats
 	runtime.ReadMemStats(&m)
 
-	tilde, _ := osutil.ExpandTilde("~")
+	tilde, _ := fs.ExpandTilde("~")
 	res := make(map[string]interface{})
 	res["myID"] = myID.String()
 	res["goroutines"] = runtime.NumGoroutine()
@@ -1259,23 +1259,35 @@ func (s *apiService) getPeerCompletion(w http.ResponseWriter, r *http.Request) {
 func (s *apiService) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
 	qs := r.URL.Query()
 	current := qs.Get("current")
+	// Default value or in case of error unmarshalling ends up being basic fs.
+	var fsType fs.FilesystemType
+	fsType.UnmarshalText([]byte(qs.Get("filesystem")))
+
 	if current == "" {
-		if roots, err := osutil.GetFilesystemRoots(); err == nil {
+		filesystem := fs.NewFilesystem(fsType, "")
+		if roots, err := filesystem.Roots(); err == nil {
 			sendJSON(w, roots)
 		} else {
 			http.Error(w, err.Error(), 500)
 		}
 		return
 	}
-	search, _ := osutil.ExpandTilde(current)
-	pathSeparator := string(os.PathSeparator)
+	search, _ := fs.ExpandTilde(current)
+	pathSeparator := string(fs.PathSeparator)
+
 	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
 		search = search + pathSeparator
 	}
-	subdirectories, _ := osutil.Glob(search + "*")
+	searchDir := filepath.Dir(search)
+	searchFile := filepath.Base(search)
+
+	fs := fs.NewFilesystem(fsType, searchDir)
+
+	subdirectories, _ := fs.Glob(searchFile + "*")
+
 	ret := make([]string, 0, len(subdirectories))
 	for _, subdirectory := range subdirectories {
-		info, err := os.Stat(subdirectory)
+		info, err := fs.Stat(subdirectory)
 		if err == nil && info.IsDir() {
 			ret = append(ret, subdirectory+pathSeparator)
 		}

cmd/syncthing/locations.go

@@ -13,7 +13,7 @@ import (
 	"strings"
 	"time"
 
-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 type locationEnum string
@@ -65,7 +65,7 @@ func expandLocations() error {
 			dir = strings.Replace(dir, "${"+varName+"}", value, -1)
 		}
 		var err error
-		dir, err = osutil.ExpandTilde(dir)
+		dir, err = fs.ExpandTilde(dir)
 		if err != nil {
 			return err
 		}
@@ -86,7 +86,7 @@ func defaultConfigDir() string {
 		return filepath.Join(os.Getenv("AppData"), "Syncthing")
 
 	case "darwin":
-		dir, err := osutil.ExpandTilde("~/Library/Application Support/Syncthing")
+		dir, err := fs.ExpandTilde("~/Library/Application Support/Syncthing")
 		if err != nil {
 			l.Fatalln(err)
 		}
@@ -96,7 +96,7 @@ func defaultConfigDir() string {
 		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
 			return filepath.Join(xdgCfg, "syncthing")
 		}
-		dir, err := osutil.ExpandTilde("~/.config/syncthing")
+		dir, err := fs.ExpandTilde("~/.config/syncthing")
 		if err != nil {
 			l.Fatalln(err)
 		}
@@ -106,7 +106,7 @@ func defaultConfigDir() string {
 
 // homeDir returns the user's home directory, or dies trying.
 func homeDir() string {
-	home, err := osutil.ExpandTilde("~")
+	home, err := fs.ExpandTilde("~")
 	if err != nil {
 		l.Fatalln(err)
 	}

cmd/syncthing/main.go

@@ -37,6 +37,7 @@ import (
 	"github.com/syncthing/syncthing/lib/dialer"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/osutil"
@@ -444,7 +445,7 @@ func openGUI() {
 }
 
 func generate(generateDir string) {
-	dir, err := osutil.ExpandTilde(generateDir)
+	dir, err := fs.ExpandTilde(generateDir)
 	if err != nil {
 		l.Fatalln("generate:", err)
 	}
@@ -1085,7 +1086,7 @@ func defaultConfig(myName string) config.Configuration {
 
 	if !noDefaultFolder {
 		l.Infoln("Default folder created and/or linked to new config")
-		defaultFolder = config.NewFolderConfiguration("default", locations[locDefFolder])
+		defaultFolder = config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, locations[locDefFolder])
 		defaultFolder.Label = "Default Folder"
 		defaultFolder.RescanIntervalS = 60
 		defaultFolder.MinDiskFree = config.Size{Value: 1, Unit: "%"}
@@ -1141,19 +1142,20 @@ func shutdown() {
 	stop <- exitSuccess
 }
 
-func ensureDir(dir string, mode os.FileMode) {
-	err := osutil.MkdirAll(dir, mode)
+func ensureDir(dir string, mode fs.FileMode) {
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
+	err := fs.MkdirAll(".", mode)
 	if err != nil {
 		l.Fatalln(err)
 	}
 
-	if fi, err := os.Stat(dir); err == nil {
+	if fi, err := fs.Stat("."); err == nil {
 		// Apprently the stat may fail even though the mkdirall passed. If it
 		// does, we'll just assume things are in order and let other things
 		// fail (like loading or creating the config...).
 		currentMode := fi.Mode() & 0777
 		if currentMode != mode {
-			err := os.Chmod(dir, mode)
+			err := fs.Chmod(".", mode)
 			// This can fail on crappy filesystems, nothing we can do about it.
 			if err != nil {
 				l.Warnln(err)
@@ -1276,22 +1278,22 @@ func cleanConfigDirectory() {
 	}
 
 	for pat, dur := range patterns {
-		pat = filepath.Join(baseDirs["config"], pat)
-		files, err := osutil.Glob(pat)
+		fs := fs.NewFilesystem(fs.FilesystemTypeBasic, baseDirs["config"])
+		files, err := fs.Glob(pat)
 		if err != nil {
 			l.Infoln("Cleaning:", err)
 			continue
 		}
 
 		for _, file := range files {
-			info, err := osutil.Lstat(file)
+			info, err := fs.Lstat(file)
 			if err != nil {
 				l.Infoln("Cleaning:", err)
 				continue
 			}
 
 			if time.Since(info.ModTime()) > dur {
-				if err = os.RemoveAll(file); err != nil {
+				if err = fs.RemoveAll(file); err != nil {
 					l.Infoln("Cleaning:", err)
 				} else {
 					l.Infoln("Cleaned away old file", filepath.Base(file))

gui/default/assets/lang/lang-de.json

@@ -10,7 +10,7 @@
     "Add Device": "Gerät hinzufügen",
     "Add Folder": "Ordner hinzufügen",
     "Add Remote Device": "Gerät hinzufügen",
-    "Add devices from the introducer to our device list, for mutually shared folders.": "Add devices from the introducer to our device list, for mutually shared folders.",
+    "Add devices from the introducer to our device list, for mutually shared folders.": "Fügt Geräte vom Verteilergerät zu der eigenen Geräteliste hinzu, um gegenseitig geteilte Ordner zu ermöglichen.",
     "Add new folder?": "Neuen Ordner hinzufügen?",
     "Address": "Adresse",
     "Addresses": "Adressen",
@@ -21,10 +21,10 @@
     "Allow Anonymous Usage Reporting?": "Übertragung von anonymen Nutzungsberichten erlauben?",
     "Allowed Networks": "Erlaubte Netzwerke",
     "Alphabetic": "Alphabetisch",
-    "An external command handles the versioning. It has to remove the file from the shared folder.": "Ein externer Befehl führt die Versionierung durch. Dazu muss die Datei aus dem geteilten Ordner entfernt werden.",
+    "An external command handles the versioning. It has to remove the file from the shared folder.": "Ein externer Befehl führt die Versionierung durch. Er muss die Datei aus dem geteilten Ordner entfernen.",
     "An external command handles the versioning. It has to remove the file from the synced folder.": "Ein externer Programmaufruf handhabt die Versionierung. Es muss die Datei aus dem zu synchronisierendem Ordner entfernen.",
     "Anonymous Usage Reporting": "Anonymer Nutzungsbericht",
-    "Any devices configured on an introducer device will be added to this device as well.": "Alle Geräte, die beim Verteiler eingetragen sind, werden auch bei diesem Gerät eingetragen",
+    "Any devices configured on an introducer device will be added to this device as well.": "Alle Geräte, die beim Verteilergerät eingetragen sind, werden auch bei diesem Gerät hinzugefügt.",
     "Automatic upgrade now offers the choice between stable releases and release candidates.": "Die automatische Aktualisierung bietet jetzt die Wahl zwischen stabilen Veröffentlichungen und Veröffentlichungskandidaten.",
     "Automatic upgrades": "Automatische Updates aktivieren",
     "Be careful!": "Vorsicht!",
@@ -32,7 +32,7 @@
     "CPU Utilization": "Prozessorauslastung",
     "Changelog": "Änderungsprotokoll",
     "Clean out after": "Löschen nach",
-    "Click to see discovery failures": "Zum Anzeigen von Gerätesuchfehlern klicken",
+    "Click to see discovery failures": "Klick um Gerätesuchfehler anzuzeigen",
     "Close": "Schließen",
     "Command": "Befehl",
     "Comment, when used at the start of a line": "Kommentar, wenn am Anfang der Zeile benutzt.",
@@ -44,7 +44,7 @@
     "Copied from original": "Vom Original kopiert",
     "Copyright © 2014-2016 the following Contributors:": "Copyright © 2014-2016 der folgenden Unterstützer:",
     "Copyright © 2014-2017 the following Contributors:": "Copyright © 2014-2017 der folgenden Unterstützer:",
-    "Creating ignore patterns, overwriting an existing file at {%path%}.": "Creating ignore patterns, overwriting an existing file at {{path}}.",
+    "Creating ignore patterns, overwriting an existing file at {%path%}.": "Erstelle Ignoriermuster, welche die existierende Datei {{path}} überschreiben.",
     "Danger!": "Achtung!",
     "Deleted": "Gelöscht",
     "Device": "Gerät",
@@ -65,24 +65,24 @@
     "Edit Device": "Gerät bearbeiten",
     "Edit Folder": "Ordner bearbeiten",
     "Editing": "Bearbeitet",
-    "Editing {%path%}.": "{{path}} wird bearbeitet.",
+    "Editing {%path%}.": "Bearbeite {{path}}.",
     "Enable NAT traversal": "NAT-Durchdringung aktivieren",
     "Enable Relaying": "Weiterleitung aktivieren",
-    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.",
-    "Enter a non-privileged port number (1024 - 65535).": "Enter a non-privileged port number (1024 - 65535).",
+    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "Geben Sie eine positive Zahl ein (z.B. \"2.35\") und wählen Sie eine Einheit. Prozentsätze sind Teil der gesamten Festplattengröße.",
+    "Enter a non-privileged port number (1024 - 65535).": "Geben Sie eine nichtprivilegierte Portnummer ein (1024 - 65535).",
     "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.": "Kommagetrennte Adressen (\"tcp://ip:port\", \"tcp://host:port\") oder \"dynamic\" eingeben, um die Adresse automatisch zu ermitteln.",
     "Enter ignore patterns, one per line.": "Geben Sie Ignoriermuster ein, eines pro Zeile.",
     "Error": "Fehler",
     "External File Versioning": "Externe Dateiversionierung",
     "Failed Items": "Fehlgeschlagene Objekte",
-    "Failure to connect to IPv6 servers is expected if there is no IPv6 connectivity.": "Es wird ein Verbindungsfehler zu IPv6-Servern erwartet, wenn es keine IPv6-Konnektivität gibt.",
+    "Failure to connect to IPv6 servers is expected if there is no IPv6 connectivity.": "Ein Verbindungsfehler zu IPv6-Servern ist zu erwarten, wenn es keine IPv6-Konnektivität gibt.",
     "File Pull Order": "Dateiübertragungsreihenfolge",
     "File Versioning": "Dateiversionierung",
     "File permission bits are ignored when looking for changes. Use on FAT file systems.": "Dateizugriffsrechte beim Suchen nach Veränderungen ignorieren. Bei FAT-Dateisystemen zu verwenden.",
-    "Files are moved to .stversions directory when replaced or deleted by Syncthing.": "Dateien werden in das .stversions-Verzeichnis verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
-    "Files are moved to .stversions folder when replaced or deleted by Syncthing.": "Wenn Syncthing Dateien ersetzt oder löscht, werden sie in den Ordner .stversions verschoben.",
-    "Files are moved to date stamped versions in a .stversions directory when replaced or deleted by Syncthing.": "Dateien werden mit einem Datumsstempel im Namen versehen und in ein .stversions-Verzeichnis verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
-    "Files are moved to date stamped versions in a .stversions folder when replaced or deleted by Syncthing.": "Dateien werden, bevor Syncthing sie löscht oder ersetzt, datiert in den Ordner .stversions verschoben.",
+    "Files are moved to .stversions directory when replaced or deleted by Syncthing.": "Dateien werden in den .stversions Ordner verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
+    "Files are moved to .stversions folder when replaced or deleted by Syncthing.": "Dateien werden in den .stversions Ordner verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
+    "Files are moved to date stamped versions in a .stversions directory when replaced or deleted by Syncthing.": "Dateien werden mit Datumsstempel versioniert und in den .stversions Ordner verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
+    "Files are moved to date stamped versions in a .stversions folder when replaced or deleted by Syncthing.": "Dateien werden mit Datumsstempel versioniert und in den .stversions Ordner verschoben, wenn sie von Syncthing ersetzt oder gelöscht werden.",
     "Files are protected from changes made on other devices, but changes made on this device will be sent to the rest of the cluster.": "Dateien sind auf diesem Gerät schreibgeschützt. Auf diesem Gerät durchgeführte Veränderungen werden aber auf den Rest des Verbunds übertragen.",
     "Folder": "Ordner",
     "Folder ID": "Ordnerkennung",
@@ -93,9 +93,9 @@
     "GUI": "GUI",
     "GUI Authentication Password": "Passwort für Zugang zur Benutzeroberfläche",
     "GUI Authentication User": "Nutzername für Zugang zur Benutzeroberfläche",
-    "GUI Listen Address": "GUI Listen Address",
-    "GUI Listen Addresses": "Adresse(n) für die Benutzeroberfläche",
-    "GUI Theme": "GUI-Theme",
+    "GUI Listen Address": "Addresse der Benutzeroberfläche",
+    "GUI Listen Addresses": "Adressen der Benutzeroberfläche",
+    "GUI Theme": "GUI Design",
     "Generate": "Generieren",
     "Global Changes": "Globale Änderungen",
     "Global Discovery": "Globale Gerätesuche",
@@ -123,7 +123,7 @@
     "Local Discovery": "Lokale Gerätesuche",
     "Local State": "Lokaler Status",
     "Local State (Total)": "Lokaler Status (Gesamt)",
-    "Major Upgrade": "Hauptversionsupgrade",
+    "Major Upgrade": "Hauptversionsupdate",
     "Master": "Master",
     "Maximum Age": "Höchstalter",
     "Metadata Only": "Nur Metadaten",
@@ -136,7 +136,7 @@
     "Newest First": "Neueste zuerst",
     "No": "Nein",
     "No File Versioning": "Keine Dateiversionierung",
-    "No upgrades": "Keine Upgrades",
+    "No upgrades": "Keine Updates",
     "Normal": "Normal",
     "Notice": "Hinweis",
     "OK": "OK",
@@ -150,16 +150,16 @@
     "Override Changes": "Änderungen überschreiben",
     "Path": "Pfad",
     "Path to the folder on the local computer. Will be created if it does not exist. The tilde character (~) can be used as a shortcut for": "Pfad zum Ordner auf dem lokalen Gerät. Ordner wird erzeugt, wenn er nicht existiert. Das Tilden-Zeichen (~) kann als Abkürzung benutzt werden für",
-    "Path where versions should be stored (leave empty for the default .stversions directory in the shared folder).": "Pfad, in dem Versionen gespeichert werden sollen (leer lassen, wenn das Standard-.stversions-Verzeichnis im geteilten Ordner verwendet werden soll).",
-    "Path where versions should be stored (leave empty for the default .stversions folder in the folder).": "Pfad in dem alte Dateiversionen gespeichert werden sollen (ohne Angabe wird der Ordner .stversions im Ordner verwendet).",
+    "Path where versions should be stored (leave empty for the default .stversions directory in the shared folder).": "Pfad in dem Versionen gespeichert werden sollen (leer lassen, wenn der Standard .stversions Ordner für den geteilten Ordner verwendet werden soll).",
+    "Path where versions should be stored (leave empty for the default .stversions folder in the folder).": "Pfad in dem Versionen gespeichert werden sollen (leer lassen, wenn der Standard .stversions Ordner für den geteilten Ordner verwendet werden soll).",
     "Pause": "Pause",
     "Pause All": "Alles pausieren",
     "Paused": "Pausiert",
-    "Please consult the release notes before performing a major upgrade.": "Bitte lesen Sie die Veröffentlichungsnotizen bevor Sie eine neue Hauptversion installieren.",
+    "Please consult the release notes before performing a major upgrade.": "Bitte lesen Sie die Veröffentlichungsnotizen bevor Sie ein neues Hauptversionsupdate installieren.",
     "Please set a GUI Authentication User and Password in the Settings dialog.": "Bitte setze einen Benutzer und ein Passwort für das GUI in den Einstellungen.",
     "Please wait": "Bitte warten",
-    "Prefix indicating that the file can be deleted if preventing directory removal": "Prefix indicating that the file can be deleted if preventing directory removal",
-    "Prefix indicating that the pattern should be matched without case sensitivity": "Prefix indicating that the pattern should be matched without case sensitivity",
+    "Prefix indicating that the file can be deleted if preventing directory removal": "Präfix, das anzeigt, dass die Datei gelöscht werden kann, wenn sie die Entfernung des Ordners verhindert",
+    "Prefix indicating that the pattern should be matched without case sensitivity": "Präfix, das anzeigt, dass das Muster ohne Beachtung der Groß-/Kleinschreibung übereinstimmen soll",
     "Preview": "Vorschau",
     "Preview Usage Report": "Vorschau des Nutzungsberichts",
     "Quick guide to supported patterns": "Schnellanleitung zu den unterstützten Mustern",
@@ -167,7 +167,7 @@
     "Random": "Zufall",
     "Reduced by ignore patterns": "Durch Ignoriermuster reduziert",
     "Release Notes": "Veröffentlichungsnotizen",
-    "Release candidates contain the latest features and fixes. They are similar to the traditional bi-weekly Syncthing releases.": "Veröffentlichungskandidaten enthalten die neuesten Funktionen und Verbesserungen. Sie ähneln den traditionellen zweiwöchentlichen Syncthing-Veröffentlichungen.",
+    "Release candidates contain the latest features and fixes. They are similar to the traditional bi-weekly Syncthing releases.": "Veröffentlichungskandidaten enthalten die neuesten Funktionen und Verbesserungen. Sie gleichen den üblichen zweiwöchentlichen Syncthing-Veröffentlichungen.",
     "Remote Devices": "Fern-Geräte",
     "Remove": "Entfernen",
     "Required identifier for the folder. Must be the same on all cluster devices.": "Erforderlicher Bezeichner für den Ordner. Muss auf allen Verbund-Geräten gleich sein.",
@@ -205,8 +205,8 @@
     "Smallest First": "Kleinstes zuerst",
     "Source Code": "Quellcode",
     "Stable releases and release candidates": "Stabile Veröffentlichungen und Veröffentlichungskandidaten",
-    "Stable releases are delayed by about two weeks. During this time they go through testing as release candidates.": "Stabile Veröffentlichungen werden ca. 2 Wochen zurückgehalten. Während dieser Zeit durchlaufen sie eine Testphase als Veröffentlichungskandidaten.",
-    "Stable releases only": "Ausschließlich stabile Veröffentlichungen",
+    "Stable releases are delayed by about two weeks. During this time they go through testing as release candidates.": "Stabile Veröffentlichungen werden ca. 2 Wochen verzögert. Während dieser Zeit durchlaufen sie eine Testphase als Veröffentlichungskandidaten.",
+    "Stable releases only": "Nur stabile Veröffentlichungen",
     "Staggered File Versioning": "Stufenweise Dateiversionierung",
     "Start Browser": "Browser starten",
     "Statistics": "Statistiken",
@@ -246,8 +246,8 @@
     "They are retried automatically and will be synced when the error is resolved.": "Sie werden automatisch heruntergeladen und werden synchronisiert, wenn der Fehler behoben wurde.",
     "This Device": "Dieses Gerät",
     "This can easily give hackers access to read and change any files on your computer.": "Dies kann dazu führen, dass Unberechtigte relativ einfach auf Ihre Dateien zugreifen und diese ändern können.",
-    "This is a major version upgrade.": "Dies ist eine neue Hauptversion.",
-    "This setting controls the free space required on the home (i.e., index database) disk.": "This setting controls the free space required on the home (i.e., index database) disk.",
+    "This is a major version upgrade.": "Dies ist ein neues Hauptversionsupdate.",
+    "This setting controls the free space required on the home (i.e., index database) disk.": "Diese Einstellung regelt den freien Speicherplatz, der für den Systemordner (d.h. Indexdatenbank) erforderlich ist.",
     "Time": "Zeit",
     "Trash Can File Versioning": "Papierkorb Dateiversionierung",
     "Type": "Typ",
@@ -256,12 +256,12 @@
     "Unused": "Ungenutzt",
     "Up to Date": "Aktuell",
     "Updated": "Aktualisiert",
-    "Upgrade": "Upgrade",
+    "Upgrade": "Update",
     "Upgrade To {%version%}": "Update auf {{version}}",
     "Upgrading": "Wird aktualisiert",
     "Upload Rate": "Upload",
     "Uptime": "Betriebszeit",
-    "Usage reporting is always enabled for candidate releases.": "Nutzungsauswertung ist für Veröffentlichungskandidaten immer aktiviert.",
+    "Usage reporting is always enabled for candidate releases.": "Nutzungsbericht ist für Veröffentlichungskandidaten immer aktiviert.",
     "Use HTTPS for GUI": "HTTPS für Benutzeroberfläche benutzen",
     "Version": "Version",
     "Versions Path": "Versionierungspfad",
@@ -273,9 +273,9 @@
     "When adding a new device, keep in mind that this device must be added on the other side too.": "Beachte beim Hinzufügen eines neuen Gerätes, dass dieses Gerät auch auf den anderen Geräten hinzugefügt werden muss.",
     "When adding a new folder, keep in mind that the Folder ID is used to tie folders together between devices. They are case sensitive and must match exactly between all devices.": "Beachte bitte beim Hinzufügen eines neuen Ordners, dass die Ordnerkennung dazu verwendet wird, Ordner zwischen Geräten zu verbinden. Die Kennung muss also auf allen Geräten gleich sein, die Groß- und Kleinschreibung muss dabei beachtet werden.",
     "Yes": "Ja",
-    "You can also select one of these nearby devices:": "You can also select one of these nearby devices:",
+    "You can also select one of these nearby devices:": "Sie können auch ein in der Nähe befindliches Geräte auswählen:",
     "You can change your choice at any time in the Settings dialog.": "Sie können Ihre Wahl jederzeit in den Einstellungen ändern.",
-    "You can read more about the two release channels at the link below.": "Über den untenstehenden Link können Sie mehr über die zwei Veröffentlichungskanäle erfahren.",
+    "You can read more about the two release channels at the link below.": "Über den folgenden Link können Sie mehr über die zwei Veröffentlichungskanäle erfahren.",
     "You must keep at least one version.": "Du musst mindestens eine Version behalten.",
     "days": "Tage",
     "directories": "Ordner",

gui/default/assets/lang/lang-el.json

@@ -159,7 +159,7 @@
     "Please set a GUI Authentication User and Password in the Settings dialog.": "Παρακαλώ όρισε στις ρυθμίσεις έναν χρήστη και έναν κωδικό πρόσβασης για τη διεπαφή.",
     "Please wait": "Παρακαλώ περιμένετε",
     "Prefix indicating that the file can be deleted if preventing directory removal": "Πρόθεμα που δείχνει ότι το αρχείο θα μπορεί να διαγραφεί αν εμποδίζει τη διαγραφή καταλόγου",
-    "Prefix indicating that the pattern should be matched without case sensitivity": "Πρόθεμα που δείχνει ότι αντιστοίχιση του προτύπου θα γίνεται χωρίς διάκριση πεζών και κεφαλαίων χαρακτήρων",
+    "Prefix indicating that the pattern should be matched without case sensitivity": "Πρόθεμα που δείχνει ότι η αντιστοίχιση προτύπου θα γίνεται χωρίς διάκριση πεζών και κεφαλαίων χαρακτήρων",
     "Preview": "Προεπισκόπηση",
     "Preview Usage Report": "Προεπισκόπηση αναφοράς χρήσης",
     "Quick guide to supported patterns": "Σύντομη βοήθεια σχετικά με τα πρότυπα αναζήτησης που υποστηρίζονται",
@@ -273,7 +273,7 @@
     "When adding a new device, keep in mind that this device must be added on the other side too.": "Θυμήσου πως όταν προσθέτεις μια νέα συσκευή, ετούτη η συσκευή θα πρέπει να προστεθεί και στην άλλη πλευρά.",
     "When adding a new folder, keep in mind that the Folder ID is used to tie folders together between devices. They are case sensitive and must match exactly between all devices.": "Όταν προσθέτεις έναν νέο φάκελο, θυμήσου πως η ταυτότητα ενός φακέλου χρησιμοποιείται για να να συσχετίσει φακέλους μεταξύ συσκευών. Η ταυτότητα του φακέλου θα πρέπει να είναι η ίδια σε όλες τις συσκευές και έχουν σημασία τα πεζά ή κεφαλαία γράμματα.",
     "Yes": "Ναι",
-    "You can also select one of these nearby devices:": "Μπορείτε επίσης να επιλέξετε μια από αυτές τις κοντινές συσκευές:",
+    "You can also select one of these nearby devices:": "Μπορείτε επίσης να επιλέξετε μια από αυτές τις γειτονικές συσκευές:",
     "You can change your choice at any time in the Settings dialog.": "Μπορείτε να αλλάξετε τη ρύθμιση αυτή ανά πάσα στιγμή στο παράθυρο «Ρυθμίσεις».",
     "You can read more about the two release channels at the link below.": "Μπορείτε να διαβάσετε περισσότερα για τα δύο κανάλια εκδόσεων στον παρακάτω σύνδεσμο.",
     "You must keep at least one version.": "Πρέπει να τηρήσεις τουλάχιστον μια έκδοση.",

gui/default/assets/lang/lang-es.json

@@ -273,7 +273,7 @@
     "When adding a new device, keep in mind that this device must be added on the other side too.": "Cuando añada un nuevo dispositivo, tenga en cuenta que este debe añadirse también en el otro lado.",
     "When adding a new folder, keep in mind that the Folder ID is used to tie folders together between devices. They are case sensitive and must match exactly between all devices.": "Cuando añada una nueva carpeta, tenga en cuenta que su ID se usa para unir carpetas entre dispositivos. Son sensibles a las mayúsculas y deben coincidir exactamente entre todos los dispositivos.",
     "Yes": "Si",
-    "You can also select one of these nearby devices:": "You can also select one of these nearby devices:",
+    "You can also select one of these nearby devices:": "También puede seleccionar uno de estos dispositivos cercanos:",
     "You can change your choice at any time in the Settings dialog.": "Puedes cambiar tu elección en cualquier momento en el panel de Ajustes.",
     "You can read more about the two release channels at the link below.": "Puedes leer más sobre los dos método de publicación de versiones en el siguiente enlace.",
     "You must keep at least one version.": "Debes mantener al menos una versión.",

gui/default/assets/lang/lang-fr.json

@@ -1,5 +1,5 @@
 {
-    "A device with that ID is already added.": "L'appareil portant cet ID est déjà présent.",
+    "A device with that ID is already added.": " L'appareil portant cet ID est déjà présent.",
     "A negative number of days doesn't make sense.": "Ce champ n'accepte qu'un entier positif ou nul.",
     "A new major version may not be compatible with previous versions.": "Une nouvelle version majeure peut présenter des incompatibilités avec les versions antérieures.",
     "API Key": "Clé API",
@@ -48,7 +48,7 @@
     "Danger!": "Attention !",
     "Deleted": "Supprimé",
     "Device": "Appareil",
-    "Device \"{%name%}\" ({%device%} at {%address%}) wants to connect. Add new device?": "\"{{name}}\" ({{device}}), actuellement à {{address}}, demande à se connecter.\nAcceptez-vous de l'ajouter à votre liste d'appareils connus ?",
+    "Device \"{%name%}\" ({%device%} at {%address%}) wants to connect. Add new device?": "\"{{name}}\" ({{device}}), appareil actuellement à {{address}}, demande à se connecter.\nAcceptez-vous de l'ajouter à votre liste d'appareils connus ?",
     "Device ID": "ID de l'appareil",
     "Device Identification": "Identifiant de l'appareil",
     "Device Name": "Nom de l'appareil",

gui/default/assets/lang/lang-it.json

@@ -97,7 +97,7 @@
     "GUI Listen Addresses": "Indirizzi dell'Interfaccia Grafica",
     "GUI Theme": "Tema GUI",
     "Generate": "Genera",
-    "Global Changes": "Modificazioni Globali",
+    "Global Changes": "Modifiche Globali",
     "Global Discovery": "Individuazione Globale",
     "Global Discovery Servers": "Server di Individuazione Globale",
     "Global State": "Stato Globale",

gui/default/assets/lang/lang-nl.json

@@ -32,7 +32,7 @@
     "CPU Utilization": "CPU-gebruik",
     "Changelog": "Logboek",
     "Clean out after": "Schoon op na",
-    "Click to see discovery failures": "Klik om ontdekkingsproblemen weer te geven",
+    "Click to see discovery failures": "Klikken om ontdekkingsproblemen weer te geven",
     "Close": "Sluiten",
     "Command": "Commando",
     "Comment, when used at the start of a line": "Reageer indien gebruikt aan het begin van een lijn.",
@@ -68,8 +68,8 @@
     "Editing {%path%}.": "Bezig met bewerken van {{path}}.",
     "Enable NAT traversal": "NAT traversal inschakelen",
     "Enable Relaying": "Doorsturen inschakelen",
-    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.",
-    "Enter a non-privileged port number (1024 - 65535).": "Enter a non-privileged port number (1024 - 65535).",
+    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "Voer een positief nummer in (bijv. \"2.35\") en selecteer een eenheid. Percentages zijn een onderdeel van de totale schijfgrootte.",
+    "Enter a non-privileged port number (1024 - 65535).": "Voer een niet-geprivilegieerd poortnummer in (1024 - 65535).",
     "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.": "Voer door komma's gescheiden (\"tcp://ip:port\", \"tcp://host:port\") adressen in of voer \"dynamisch\" in om automatische ontdekking van het adres uit te voeren.",
     "Enter ignore patterns, one per line.": "Voer negeerpatronen in, één per regel.",
     "Error": "Fout",
@@ -158,8 +158,8 @@
     "Please consult the release notes before performing a major upgrade.": "Lees eerst de release notes voordat u een grote update uitvoert.",
     "Please set a GUI Authentication User and Password in the Settings dialog.": "Stel een gebruikersnaam en wachtwoord in bij 'Instellingen'.",
     "Please wait": "Even geduld",
-    "Prefix indicating that the file can be deleted if preventing directory removal": "Prefix indicating that the file can be deleted if preventing directory removal",
-    "Prefix indicating that the pattern should be matched without case sensitivity": "Prefix indicating that the pattern should be matched without case sensitivity",
+    "Prefix indicating that the file can be deleted if preventing directory removal": "Voorvoegsel dat aangeeft dat het bestand kan worden verwijderd als het bestand het verwijderen van een map voorkomt",
+    "Prefix indicating that the pattern should be matched without case sensitivity": "Voorvoegsel dat aangeeft dat het patroon hoofdletterongevoelig moet worden vergeleken",
     "Preview": "Preview",
     "Preview Usage Report": "Preview gebruiksstatistieken",
     "Quick guide to supported patterns": "Snelgids voor ondersteunde patronen",
@@ -247,7 +247,7 @@
     "This Device": "Dit apparaat",
     "This can easily give hackers access to read and change any files on your computer.": "Dit kan kwaadwilligen eenvoudig toegang geven tot het lezen en wijzigen van bestanden op jouw computer.",
     "This is a major version upgrade.": "Dit is een grote update.",
-    "This setting controls the free space required on the home (i.e., index database) disk.": "This setting controls the free space required on the home (i.e., index database) disk.",
+    "This setting controls the free space required on the home (i.e., index database) disk.": "Deze instelling beheert de benodigde vrije ruimte op de home (index database) schijf.",
     "Time": "Tijd",
     "Trash Can File Versioning": "Versiebeheer bestanden prullenbak",
     "Type": "Type",
@@ -273,7 +273,7 @@
     "When adding a new device, keep in mind that this device must be added on the other side too.": "Wanneer een nieuw toestel wordt toegevoegd, houd er dan rekening mee dat dit toestel ook aan de andere kant moet worden toegevoegd.",
     "When adding a new folder, keep in mind that the Folder ID is used to tie folders together between devices. They are case sensitive and must match exactly between all devices.": "Houd er bij het toevoegen van nieuwe mappen rekening mee dat het map-ID gebruikt wordt om mappen tussen apparaten te verbinden. Dit ID is hoofdlettergevoelig en moet identiek zijn op andere apparaten.",
     "Yes": "Ja",
-    "You can also select one of these nearby devices:": "You can also select one of these nearby devices:",
+    "You can also select one of these nearby devices:": "U kunt ook een van de apparaten die dichtbij zijn selecteren:",
     "You can change your choice at any time in the Settings dialog.": "Je kan je keuze op elk moment aanpassen in de Instellingen.",
     "You can read more about the two release channels at the link below.": "Je kan meer te weten komen over de twee uitgavekanalen via de link hieronder.",
     "You must keep at least one version.": "Minstens 1 versie moet bewaard blijven.",

gui/default/assets/lang/lang-pl.json

@@ -1,5 +1,5 @@
 {
-    "A device with that ID is already added.": "Urządzenie o tym ID jest już dodane.",
+    "A device with that ID is already added.": "Urządzenie o tym ID już istnieje.",
     "A negative number of days doesn't make sense.": "Ujemna ilość dni nie ma sensu.",
     "A new major version may not be compatible with previous versions.": "Nowa wersja może być niekompatybilna z poprzednimi wersjami.",
     "API Key": "Klucz API",

gui/default/assets/lang/lang-zh-CN.json

@@ -10,7 +10,7 @@
     "Add Device": "添加设备",
     "Add Folder": "添加文件夹",
     "Add Remote Device": "添加远程设备",
-    "Add devices from the introducer to our device list, for mutually shared folders.": "添加介绍人中的设备到我们的设备列表，以互相共享文件夹。",
+    "Add devices from the introducer to our device list, for mutually shared folders.": "将此新设备上拥有的“远程设备”都自动添加到您这边的“远程设备”列表中（如果它们跟您存在相同的文件夹的话）",
     "Add new folder?": "添加新文件夹？",
     "Address": "地址",
     "Addresses": "地址列表",
@@ -24,7 +24,7 @@
     "An external command handles the versioning. It has to remove the file from the shared folder.": "使用外部命令接管版本控制。该命令必须自行从共享文件夹中删除该文件。",
     "An external command handles the versioning. It has to remove the file from the synced folder.": "使用外部命令接管版本控制。该命令必须自行从同步文件夹中删除该文件。",
     "Anonymous Usage Reporting": "匿名使用报告",
-    "Any devices configured on an introducer device will be added to this device as well.": "在介绍人设备上被添加的其它设备，也将会被添加到本机。",
+    "Any devices configured on an introducer device will be added to this device as well.": "在中介设备上添加的任何“远程设备”，也会被自动添加到本机的“远程设备”列表。",
     "Automatic upgrade now offers the choice between stable releases and release candidates.": "自动升级现提供了稳定版本和发布候选版之间的选择。",
     "Automatic upgrades": "自动升级",
     "Be careful!": "小心！",
@@ -32,7 +32,7 @@
     "CPU Utilization": "CPU使用率",
     "Changelog": "更新日志",
     "Clean out after": "在该时间后清除",
-    "Click to see discovery failures": "点击查看发现错误",
+    "Click to see discovery failures": "点击查看设备发现错误",
     "Close": "关闭",
     "Command": "命令",
     "Comment, when used at the start of a line": "注释，在行首使用",
@@ -55,27 +55,27 @@
     "Devices": "设备",
     "Disconnected": "连接已断开",
     "Discovered": "已发现",
-    "Discovery": "发现",
-    "Discovery Failures": "发现错误",
+    "Discovery": "设备发现",
+    "Discovery Failures": "设备发现错误",
     "Documentation": "文档",
     "Download Rate": "下载速度",
     "Downloaded": "已下载",
     "Downloading": "下载中",
     "Edit": "选项",
-    "Edit Device": "编辑设备",
-    "Edit Folder": "编辑文件夹",
+    "Edit Device": "修改设备选项",
+    "Edit Folder": "修改文件夹选项",
     "Editing": "正在编辑",
     "Editing {%path%}.": "正在编辑 {{path}}。",
     "Enable NAT traversal": "启用 NAT 遍历",
     "Enable Relaying": "开启中继",
-    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "输入一个非负数（例如“2.35”）并选择单位。百分比是磁盘总大小的一部分。",
+    "Enter a non-negative number (e.g., \"2.35\") and select a unit. Percentages are as part of the total disk size.": "输入一个非负数（例如“2.35”）并选择单位。%表示占磁盘总容量的百分比。",
     "Enter a non-privileged port number (1024 - 65535).": "输入一个非特权的端口号 (1024 - 65535)。",
-    "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.": "输入以半角逗号分隔的 (\"tcp://ip:port\", \"tcp://host:port\") 设置可用地址列表，或者输入 \"dynamic\" 表示自动发现地址。",
+    "Enter comma separated  (\"tcp://ip:port\", \"tcp://host:port\") addresses or \"dynamic\" to perform automatic discovery of the address.": "输入以半角逗号分隔的 (\"tcp://ip:port\", \"tcp://host:port\") 设备地址列表，或者输入 \"dynamic\" 以自动发现设备地址。",
     "Enter ignore patterns, one per line.": "请输入忽略表达式，每行一条。",
     "Error": "错误",
     "External File Versioning": "外部版本控制",
     "Failed Items": "失败的项目",
-    "Failure to connect to IPv6 servers is expected if there is no IPv6 connectivity.": "如果无 IPv6 连接则预期连接到 IPv6 服务器会失败。",
+    "Failure to connect to IPv6 servers is expected if there is no IPv6 connectivity.": "如果本机没有配置IPv6，则无法连接IPv6服务器是正常的。",
     "File Pull Order": "文件拉取顺序",
     "File Versioning": "版本控制",
     "File permission bits are ignored when looking for changes. Use on FAT file systems.": "当查找文件更改时，忽略文件权限位。用在 FAT 文件系统上。",
@@ -97,7 +97,7 @@
     "GUI Listen Addresses": "图形管理界面监听地址",
     "GUI Theme": "GUI 主题",
     "Generate": "生成",
-    "Global Changes": "全局更改",
+    "Global Changes": "全局变更",
     "Global Discovery": "全球发现",
     "Global Discovery Servers": "全球发现服务器",
     "Global State": "全局状态",
@@ -109,7 +109,7 @@
     "Incoming Rate Limit (KiB/s)": "下载速率限制 (KiB/s)",
     "Incorrect configuration may damage your folder contents and render Syncthing inoperable.": "错误的配置可能损坏您文件夹内的内容，使得 Syncthing 无法工作。",
     "Introduced By": "介绍自",
-    "Introducer": "介绍人设备",
+    "Introducer": "作为中介",
     "Inversion of the given condition (i.e. do not exclude)": "对本条件取反（例如：不要排除某项）",
     "Keep Versions": "保留版本数量",
     "Largest First": "大文件优先",

gui/default/index.html

@@ -394,7 +394,7 @@
                     </tr>
                     <tr>
                       <th><span class="fa fa-fw fa-share-alt"></span>&nbsp;<span translate>Shared With</span></th>
-                      <td class="text-right">{{sharesFolder(folder)}}</td>
+                      <td class="text-right" title="{{sharesFolder(folder)}}">{{sharesFolder(folder)}}</td>
                     </tr>
                     <tr>
                       <th><span class="fa fa-fw fa-clock-o"></span>&nbsp;<span translate>Last Scan</span></th>
@@ -645,7 +645,7 @@
                     </tr>
                     <tr ng-if="deviceFolders(deviceCfg).length > 0">
                       <th><span class="fa fa-fw fa-folder"></span>&nbsp;<span translate>Folders</span></th>
-                      <td class="text-right">{{deviceFolders(deviceCfg).map(folderLabel).join(", ")}}</td>
+                      <td class="text-right" title="{{deviceFolders(deviceCfg).map(folderLabel).join(", ")}}">{{deviceFolders(deviceCfg).map(folderLabel).join(", ")}}</td>
                     </tr>
                   </tbody>
                 </table>

gui/default/syncthing/core/notifications.html

@@ -40,4 +40,4 @@
       <div class="clearfix"></div>
     </div>
   </div>
-</notification>
+</notification>

gui/default/syncthing/core/syncthingController.js

@@ -477,7 +477,7 @@ angular.module('syncthing.core')
                 $scope.completion[device]._total = 100;
                 $scope.completion[device]._needBytes = 0;
             } else {
-                $scope.completion[device]._total = 100 * (1 - needed / total);
+                $scope.completion[device]._total = Math.floor(100 * (1 - needed / total));
                 $scope.completion[device]._needBytes = needed
             }
 
@@ -622,6 +622,10 @@ angular.module('syncthing.core')
             return path;
         }
 
+        function shouldSetDefaultFolderPath() {
+            return $scope.config.options && $scope.config.options.defaultFolderPath && !$scope.editingExisting && $scope.folderEditor.folderPath.$pristine
+        }
+
         $scope.neededPageChanged = function (page) {
             $scope.neededCurrentPage = page;
             refreshNeed($scope.neededFolder);
@@ -1388,14 +1392,14 @@ angular.module('syncthing.core')
         });
 
         $scope.$watch('currentFolder.label', function (newvalue) {
-            if (!$scope.config.options || !$scope.config.options.defaultFolderPath || $scope.editingExisting || !$scope.folderEditor.folderPath.$pristine || !newvalue) {
+            if (!newvalue || !shouldSetDefaultFolderPath()) {
                 return;
             }
             $scope.currentFolder.path = pathJoin($scope.config.options.defaultFolderPath, newvalue);
         });
 
         $scope.$watch('currentFolder.id', function (newvalue) {
-            if (!$scope.config.options || !$scope.config.options.defaultFolderPath || !$scope.folderEditor.folderPath.$pristine || !newvalue || $scope.currentFolder.label) {
+            if (!newvalue || !shouldSetDefaultFolderPath() || $scope.currentFolder.label) {
                 return;
             }
             $scope.currentFolder.path = pathJoin($scope.config.options.defaultFolderPath, newvalue);

gui/default/syncthing/folder/editFolderModalView.html

@@ -180,7 +180,7 @@
               <label translate for="externalCommand">Command</label>
               <input name="externalCommand" id="externalCommand" class="form-control" type="text" ng-model="currentFolder.externalCommand" required="" aria-required="true" />
               <p class="help-block">
-                <span translate ng-if="folderEditor.externalCommand.$valid || folderEditor.externalCommand.$pristine">The first command line parameter is the folder path and the second parameter is the relative path in the folder.</span>
+                <span translate ng-if="folderEditor.externalCommand.$valid || folderEditor.externalCommand.$pristine">See external versioner help for supported templated command line parameters.</span>
                 <span translate ng-if="folderEditor.externalCommand.$error.required && folderEditor.externalCommand.$dirty">The path cannot be blank.</span>
               </p>
             </div>

lib/config/config.go

@@ -17,10 +17,13 @@ import (
 	"net/url"
 	"os"
 	"path"
+	"path/filepath"
+	"runtime"
 	"sort"
 	"strconv"
 	"strings"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/upgrade"
@@ -29,7 +32,7 @@ import (
 
 const (
 	OldestHandledVersion = 10
-	CurrentVersion       = 20
+	CurrentVersion       = 22
 	MaxRescanIntervalS   = 365 * 24 * 60 * 60
 )
 
@@ -314,6 +317,12 @@ func (cfg *Configuration) clean() error {
 	if cfg.Version == 19 {
 		convertV19V20(cfg)
 	}
+	if cfg.Version == 20 {
+		convertV20V21(cfg)
+	}
+	if cfg.Version == 21 {
+		convertV21V22(cfg)
+	}
 
 	// Build a list of available devices
 	existingDevices := make(map[protocol.DeviceID]bool)
@@ -363,6 +372,45 @@ func (cfg *Configuration) clean() error {
 	return nil
 }
 
+func convertV21V22(cfg *Configuration) {
+	for i := range cfg.Folders {
+		cfg.Folders[i].FilesystemType = fs.FilesystemTypeBasic
+		// Migrate to templated external versioner commands
+		if cfg.Folders[i].Versioning.Type == "external" {
+			cfg.Folders[i].Versioning.Params["command"] += " %FOLDER_PATH% %FILE_PATH%"
+		}
+	}
+
+	cfg.Version = 22
+}
+
+func convertV20V21(cfg *Configuration) {
+	for _, folder := range cfg.Folders {
+		if folder.FilesystemType != fs.FilesystemTypeBasic {
+			continue
+		}
+		switch folder.Versioning.Type {
+		case "simple", "trashcan":
+			// Clean out symlinks in the known place
+			cleanSymlinks(folder.Filesystem(), ".stversions")
+		case "staggered":
+			versionDir := folder.Versioning.Params["versionsPath"]
+			if versionDir == "" {
+				// default place
+				cleanSymlinks(folder.Filesystem(), ".stversions")
+			} else if filepath.IsAbs(versionDir) {
+				// absolute
+				cleanSymlinks(fs.NewFilesystem(fs.FilesystemTypeBasic, versionDir), ".")
+			} else {
+				// relative to folder
+				cleanSymlinks(folder.Filesystem(), versionDir)
+			}
+		}
+	}
+
+	cfg.Version = 21
+}
+
 func convertV19V20(cfg *Configuration) {
 	cfg.Options.MinHomeDiskFree = Size{Value: cfg.Options.DeprecatedMinHomeDiskFreePct, Unit: "%"}
 	cfg.Options.DeprecatedMinHomeDiskFreePct = 0
@@ -399,9 +447,7 @@ func convertV17V18(cfg *Configuration) {
 }
 
 func convertV16V17(cfg *Configuration) {
-	for i := range cfg.Folders {
-		cfg.Folders[i].Fsync = true
-	}
+	// Fsync = true removed
 
 	cfg.Version = 17
 }
@@ -640,3 +686,23 @@ loop:
 	}
 	return devices[0:count]
 }
+
+func cleanSymlinks(filesystem fs.Filesystem, dir string) {
+	if runtime.GOOS == "windows" {
+		// We don't do symlinks on Windows. Additionally, there may
+		// be things that look like symlinks that are not, which we
+		// should leave alone. Deduplicated files, for example.
+		return
+	}
+	filesystem.Walk(dir, func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsSymlink() {
+			l.Infoln("Removing incorrectly versioned symlink", path)
+			filesystem.Remove(path)
+			return fs.SkipDir
+		}
+		return nil
+	})
+}

lib/config/config_test.go

@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"github.com/d4l3k/messagediff"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 )
 
@@ -103,7 +104,8 @@ func TestDeviceConfig(t *testing.T) {
 		expectedFolders := []FolderConfiguration{
 			{
 				ID:              "test",
-				RawPath:         "testdata",
+				FilesystemType:  fs.FilesystemTypeBasic,
+				Path:            "testdata",
 				Devices:         []FolderDeviceConfiguration{{DeviceID: device1}, {DeviceID: device4}},
 				Type:            FolderTypeSendOnly,
 				RescanIntervalS: 600,
@@ -113,7 +115,6 @@ func TestDeviceConfig(t *testing.T) {
 				AutoNormalize:   true,
 				MinDiskFree:     Size{1, "%"},
 				MaxConflicts:    -1,
-				Fsync:           true,
 				Versioning: VersioningConfiguration{
 					Params: map[string]string{},
 				},
@@ -121,15 +122,11 @@ func TestDeviceConfig(t *testing.T) {
 			},
 		}
 
-		// The cachedPath will have been resolved to an absolute path,
+		// The cachedFilesystem will have been resolved to an absolute path,
 		// depending on where the tests are running. Zero it out so we don't
 		// fail based on that.
 		for i := range cfg.Folders {
-			cfg.Folders[i].cachedPath = ""
-		}
-
-		if runtime.GOOS != "windows" {
-			expectedFolders[0].RawPath += string(filepath.Separator)
+			cfg.Folders[i].cachedFilesystem = nil
 		}
 
 		expectedDevices := []DeviceConfiguration{
@@ -377,16 +374,17 @@ func TestVersioningConfig(t *testing.T) {
 }
 
 func TestIssue1262(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skipf("path gets converted to absolute as part of the filesystem initialization on linux")
+	}
+
 	cfg, err := Load("testdata/issue-1262.xml", device4)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	actual := cfg.Folders()["test"].RawPath
-	expected := "e:/"
-	if runtime.GOOS == "windows" {
-		expected = `e:\`
-	}
+	actual := cfg.Folders()["test"].Filesystem().URI()
+	expected := `e:\`
 
 	if actual != expected {
 		t.Errorf("%q != %q", actual, expected)
@@ -416,43 +414,12 @@ func TestIssue1750(t *testing.T) {
 	}
 }
 
-func TestWindowsPaths(t *testing.T) {
-	if runtime.GOOS != "windows" {
-		t.Skip("Not useful on non-Windows")
-		return
-	}
-
-	folder := FolderConfiguration{
-		RawPath: `e:\`,
-	}
-
-	expected := `\\?\e:\`
-	actual := folder.Path()
-	if actual != expected {
-		t.Errorf("%q != %q", actual, expected)
-	}
-
-	folder.RawPath = `\\192.0.2.22\network\share`
-	expected = folder.RawPath
-	actual = folder.Path()
-	if actual != expected {
-		t.Errorf("%q != %q", actual, expected)
-	}
-
-	folder.RawPath = `relative\path`
-	expected = folder.RawPath
-	actual = folder.Path()
-	if actual == expected || !strings.HasPrefix(actual, "\\\\?\\") {
-		t.Errorf("%q == %q, expected absolutification", actual, expected)
-	}
-}
-
 func TestFolderPath(t *testing.T) {
 	folder := FolderConfiguration{
-		RawPath: "~/tmp",
+		Path: "~/tmp",
 	}
 
-	realPath := folder.Path()
+	realPath := folder.Filesystem().URI()
 	if !filepath.IsAbs(realPath) {
 		t.Error(realPath, "should be absolute")
 	}
@@ -677,8 +644,8 @@ func TestEmptyFolderPaths(t *testing.T) {
 		t.Fatal(err)
 	}
 	folder := wrapper.Folders()["f1"]
-	if folder.Path() != "" {
-		t.Errorf("Expected %q to be empty", folder.Path())
+	if folder.cachedFilesystem != nil {
+		t.Errorf("Expected %q to be empty", folder.cachedFilesystem)
 	}
 }
 

lib/config/folderconfiguration.go

@@ -8,19 +8,17 @@ package config
 
 import (
 	"fmt"
-	"os"
-	"path/filepath"
 	"runtime"
-	"strings"
 
-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 )
 
 type FolderConfiguration struct {
 	ID                    string                      `xml:"id,attr" json:"id"`
 	Label                 string                      `xml:"label,attr" json:"label"`
-	RawPath               string                      `xml:"path,attr" json:"path"`
+	FilesystemType        fs.FilesystemType           `xml:"filesystemType" json:"filesystemType"`
+	Path                  string                      `xml:"path,attr" json:"path"`
 	Type                  FolderType                  `xml:"type,attr" json:"type"`
 	Devices               []FolderDeviceConfiguration `xml:"device" json:"devices"`
 	RescanIntervalS       int                         `xml:"rescanIntervalS,attr" json:"rescanIntervalS"`
@@ -39,11 +37,10 @@ type FolderConfiguration struct {
 	MaxConflicts          int                         `xml:"maxConflicts" json:"maxConflicts"`
 	DisableSparseFiles    bool                        `xml:"disableSparseFiles" json:"disableSparseFiles"`
 	DisableTempIndexes    bool                        `xml:"disableTempIndexes" json:"disableTempIndexes"`
-	Fsync                 bool                        `xml:"fsync" json:"fsync"`
 	Paused                bool                        `xml:"paused" json:"paused"`
 	WeakHashThresholdPct  int                         `xml:"weakHashThresholdPct" json:"weakHashThresholdPct"` // Use weak hash if more than X percent of the file has changed. Set to -1 to always use weak hash.
 
-	cachedPath string
+	cachedFilesystem fs.Filesystem
 
 	DeprecatedReadOnly       bool    `xml:"ro,attr,omitempty" json:"-"`
 	DeprecatedMinDiskFreePct float64 `xml:"minDiskFreePct,omitempty" json:"-"`
@@ -54,10 +51,11 @@ type FolderDeviceConfiguration struct {
 	IntroducedBy protocol.DeviceID `xml:"introducedBy,attr" json:"introducedBy"`
 }
 
-func NewFolderConfiguration(id, path string) FolderConfiguration {
+func NewFolderConfiguration(id string, fsType fs.FilesystemType, path string) FolderConfiguration {
 	f := FolderConfiguration{
-		ID:      id,
-		RawPath: path,
+		ID:             id,
+		FilesystemType: fsType,
+		Path:           path,
 	}
 	f.prepare()
 	return f
@@ -71,53 +69,57 @@ func (f FolderConfiguration) Copy() FolderConfiguration {
 	return c
 }
 
-func (f FolderConfiguration) Path() string {
+func (f FolderConfiguration) Filesystem() fs.Filesystem {
 	// This is intentionally not a pointer method, because things like
-	// cfg.Folders["default"].Path() should be valid.
-
-	if f.cachedPath == "" && f.RawPath != "" {
-		l.Infoln("bug: uncached path call (should only happen in tests)")
-		return f.cleanedPath()
+	// cfg.Folders["default"].Filesystem() should be valid.
+	if f.cachedFilesystem == nil && f.Path != "" {
+		l.Infoln("bug: uncached filesystem call (should only happen in tests)")
+		return fs.NewFilesystem(f.FilesystemType, f.Path)
 	}
-	return f.cachedPath
+	return f.cachedFilesystem
 }
 
 func (f *FolderConfiguration) CreateMarker() error {
 	if !f.HasMarker() {
-		marker := filepath.Join(f.Path(), ".stfolder")
-		fd, err := os.Create(marker)
+		fs := f.Filesystem()
+		fd, err := fs.Create(".stfolder")
 		if err != nil {
 			return err
 		}
 		fd.Close()
-		if err := osutil.SyncDir(filepath.Dir(marker)); err != nil {
-			l.Infof("fsync %q failed: %v", filepath.Dir(marker), err)
+		if dir, err := fs.Open("."); err == nil {
+			if serr := dir.Sync(); err != nil {
+				l.Infof("fsync %q failed: %v", ".", serr)
+			}
+		} else {
+			l.Infof("fsync %q failed: %v", ".", err)
 		}
-		osutil.HideFile(marker)
+		fs.Hide(".stfolder")
 	}
 
 	return nil
 }
 
 func (f *FolderConfiguration) HasMarker() bool {
-	_, err := os.Stat(filepath.Join(f.Path(), ".stfolder"))
+	_, err := f.Filesystem().Stat(".stfolder")
 	return err == nil
 }
 
 func (f *FolderConfiguration) CreateRoot() (err error) {
 	// Directory permission bits. Will be filtered down to something
 	// sane by umask on Unixes.
-	permBits := os.FileMode(0777)
+	permBits := fs.FileMode(0777)
 	if runtime.GOOS == "windows" {
 		// Windows has no umask so we must chose a safer set of bits to
 		// begin with.
 		permBits = 0700
 	}
 
-	if _, err = os.Stat(f.Path()); os.IsNotExist(err) {
-		if err = osutil.MkdirAll(f.Path(), permBits); err != nil {
-			l.Warnf("Creating directory for %v: %v",
-				f.Description(), err)
+	filesystem := f.Filesystem()
+
+	if _, err = filesystem.Stat("."); fs.IsNotExist(err) {
+		if err = filesystem.MkdirAll(".", permBits); err != nil {
+			l.Warnf("Creating directory for %v: %v", f.Description(), err)
 		}
 	}
 
@@ -140,24 +142,10 @@ func (f *FolderConfiguration) DeviceIDs() []protocol.DeviceID {
 }
 
 func (f *FolderConfiguration) prepare() {
-	if f.RawPath != "" {
-		// The reason it's done like this:
-		// C:          ->  C:\            ->  C:\        (issue that this is trying to fix)
-		// C:\somedir  ->  C:\somedir\    ->  C:\somedir
-		// C:\somedir\ ->  C:\somedir\\   ->  C:\somedir
-		// This way in the tests, we get away without OS specific separators
-		// in the test configs.
-		f.RawPath = filepath.Dir(f.RawPath + string(filepath.Separator))
-
-		// If we're not on Windows, we want the path to end with a slash to
-		// penetrate symlinks. On Windows, paths must not end with a slash.
-		if runtime.GOOS != "windows" && f.RawPath[len(f.RawPath)-1] != filepath.Separator {
-			f.RawPath = f.RawPath + string(filepath.Separator)
-		}
+	if f.Path != "" {
+		f.cachedFilesystem = fs.NewFilesystem(f.FilesystemType, f.Path)
 	}
 
-	f.cachedPath = f.cleanedPath()
-
 	if f.RescanIntervalS > MaxRescanIntervalS {
 		f.RescanIntervalS = MaxRescanIntervalS
 	} else if f.RescanIntervalS < 0 {
@@ -173,43 +161,6 @@ func (f *FolderConfiguration) prepare() {
 	}
 }
 
-func (f *FolderConfiguration) cleanedPath() string {
-	if f.RawPath == "" {
-		return ""
-	}
-
-	cleaned := f.RawPath
-
-	// Attempt tilde expansion; leave unchanged in case of error
-	if path, err := osutil.ExpandTilde(cleaned); err == nil {
-		cleaned = path
-	}
-
-	// Attempt absolutification; leave unchanged in case of error
-	if !filepath.IsAbs(cleaned) {
-		// Abs() looks like a fairly expensive syscall on Windows, while
-		// IsAbs() is a whole bunch of string mangling. I think IsAbs() may be
-		// somewhat faster in the general case, hence the outer if...
-		if path, err := filepath.Abs(cleaned); err == nil {
-			cleaned = path
-		}
-	}
-
-	// Attempt to enable long filename support on Windows. We may still not
-	// have an absolute path here if the previous steps failed.
-	if runtime.GOOS == "windows" && filepath.IsAbs(cleaned) && !strings.HasPrefix(f.RawPath, `\\`) {
-		return `\\?\` + cleaned
-	}
-
-	// If we're not on Windows, we want the path to end with a slash to
-	// penetrate symlinks. On Windows, paths must not end with a slash.
-	if runtime.GOOS != "windows" && cleaned[len(cleaned)-1] != filepath.Separator {
-		cleaned = cleaned + string(filepath.Separator)
-	}
-
-	return cleaned
-}
-
 type FolderDeviceConfigurationList []FolderDeviceConfiguration
 
 func (l FolderDeviceConfigurationList) Less(a, b int) bool {

lib/config/testdata/v21.xml

@@ -0,0 +1,15 @@
+<configuration version="21">
+    <folder id="test" path="testdata" type="readonly" ignorePerms="false" rescanIntervalS="600" autoNormalize="true">
+        <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR"></device>
+        <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"></device>
+        <minDiskFree unit="%">1</minDiskFree>
+        <maxConflicts>-1</maxConflicts>
+        <fsync>true</fsync>
+    </folder>
+    <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR" name="node one" compression="metadata">
+        <address>tcp://a</address>
+    </device>
+    <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2" name="node two" compression="metadata">
+        <address>tcp://b</address>
+    </device>
+</configuration>

lib/config/testdata/v22.xml

@@ -0,0 +1,16 @@
+<configuration version="22">
+    <folder id="test" path="testdata" type="readonly" ignorePerms="false" rescanIntervalS="600" autoNormalize="true">
+        <filesystemType>basic</filesystemType>
+        <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR"></device>
+        <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2"></device>
+        <minDiskFree unit="%">1</minDiskFree>
+        <maxConflicts>-1</maxConflicts>
+        <fsync>true</fsync>
+    </folder>
+    <device id="AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR" name="node one" compression="metadata">
+        <address>tcp://a</address>
+    </device>
+    <device id="P56IOI7-MZJNU2Y-IQGDREY-DM2MGTI-MGL3BXN-PQ6W5BM-TBBZ4TJ-XZWICQ2" name="node two" compression="metadata">
+        <address>tcp://b</address>
+    </device>
+</configuration>

lib/config/testdata/versioningconfig.xml

@@ -1,5 +1,5 @@
-<configuration version="10">
-    <folder id="test" directory="testdata/" ro="true">
+<configuration version="22">
+    <folder id="test" path="testdata" type="readonly" ignorePerms="false" rescanIntervalS="600" autoNormalize="true">
         <versioning type="simple">
             <param key="foo" val="bar"/>
             <param key="baz" val="quux"/>

lib/db/set.go

@@ -25,6 +25,7 @@ import (
 type FileSet struct {
 	sequence   int64 // Our local sequence number
 	folder     string
+	fs         fs.Filesystem
 	db         *Instance
 	blockmap   *BlockMap
 	localSize  sizeTracker
@@ -113,10 +114,11 @@ func (s *sizeTracker) Size() Counts {
 	return s.Counts
 }
 
-func NewFileSet(folder string, db *Instance) *FileSet {
+func NewFileSet(folder string, fs fs.Filesystem, db *Instance) *FileSet {
 	var s = FileSet{
 		remoteSequence: make(map[protocol.DeviceID]int64),
 		folder:         folder,
+		fs:             fs,
 		db:             db,
 		blockmap:       NewBlockMap(db, db.folderIdx.ID([]byte(folder))),
 		updateMutex:    sync.NewMutex(),
@@ -303,7 +305,7 @@ func (s *FileSet) SetIndexID(device protocol.DeviceID, id protocol.IndexID) {
 func (s *FileSet) MtimeFS() *fs.MtimeFS {
 	prefix := s.db.mtimesKey([]byte(s.folder))
 	kv := NewNamespacedKV(s.db, string(prefix))
-	return fs.NewMtimeFS(fs.DefaultFilesystem, kv)
+	return fs.NewMtimeFS(s.fs, kv)
 }
 
 func (s *FileSet) ListDevices() []protocol.DeviceID {

lib/db/set_test.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/d4l3k/messagediff"
 	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 )
 
@@ -97,7 +98,7 @@ func (l fileList) String() string {
 func TestGlobalSet(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	m := db.NewFileSet("test", ldb)
+	m := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	local0 := fileList{
 		protocol.FileInfo{Name: "a", Sequence: 1, Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}, Blocks: genBlocks(1)},
@@ -312,7 +313,7 @@ func TestGlobalSet(t *testing.T) {
 func TestNeedWithInvalid(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	localHave := fileList{
 		protocol.FileInfo{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}, Blocks: genBlocks(1)},
@@ -349,7 +350,7 @@ func TestNeedWithInvalid(t *testing.T) {
 func TestUpdateToInvalid(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	localHave := fileList{
 		protocol.FileInfo{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}, Blocks: genBlocks(1)},
@@ -381,7 +382,7 @@ func TestUpdateToInvalid(t *testing.T) {
 func TestInvalidAvailability(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	remote0Have := fileList{
 		protocol.FileInfo{Name: "both", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1001}}}, Blocks: genBlocks(2)},
@@ -419,7 +420,7 @@ func TestInvalidAvailability(t *testing.T) {
 func TestGlobalReset(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	m := db.NewFileSet("test", ldb)
+	m := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	local := []protocol.FileInfo{
 		{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
@@ -457,7 +458,7 @@ func TestGlobalReset(t *testing.T) {
 func TestNeed(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	m := db.NewFileSet("test", ldb)
+	m := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	local := []protocol.FileInfo{
 		{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
@@ -495,7 +496,7 @@ func TestNeed(t *testing.T) {
 func TestSequence(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	m := db.NewFileSet("test", ldb)
+	m := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	local1 := []protocol.FileInfo{
 		{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
@@ -525,7 +526,7 @@ func TestSequence(t *testing.T) {
 func TestListDropFolder(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s0 := db.NewFileSet("test0", ldb)
+	s0 := db.NewFileSet("test0", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 	local1 := []protocol.FileInfo{
 		{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
 		{Name: "b", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
@@ -533,7 +534,7 @@ func TestListDropFolder(t *testing.T) {
 	}
 	s0.Replace(protocol.LocalDeviceID, local1)
 
-	s1 := db.NewFileSet("test1", ldb)
+	s1 := db.NewFileSet("test1", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 	local2 := []protocol.FileInfo{
 		{Name: "d", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}},
 		{Name: "e", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}},
@@ -575,7 +576,7 @@ func TestListDropFolder(t *testing.T) {
 func TestGlobalNeedWithInvalid(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test1", ldb)
+	s := db.NewFileSet("test1", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	rem0 := fileList{
 		protocol.FileInfo{Name: "a", Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1002}}}, Blocks: genBlocks(4)},
@@ -612,7 +613,7 @@ func TestGlobalNeedWithInvalid(t *testing.T) {
 func TestLongPath(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	var b bytes.Buffer
 	for i := 0; i < 100; i++ {
@@ -642,7 +643,7 @@ func TestCommitted(t *testing.T) {
 
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	local := []protocol.FileInfo{
 		{Name: string("file"), Version: protocol.Vector{Counters: []protocol.Counter{{ID: myID, Value: 1000}}}},
@@ -688,7 +689,7 @@ func BenchmarkUpdateOneFile(b *testing.B) {
 		os.RemoveAll("testdata/benchmarkupdate.db")
 	}()
 
-	m := db.NewFileSet("test", ldb)
+	m := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 	m.Replace(protocol.LocalDeviceID, local0)
 	l := local0[4:5]
 
@@ -703,7 +704,7 @@ func BenchmarkUpdateOneFile(b *testing.B) {
 func TestIndexID(t *testing.T) {
 	ldb := db.OpenMemory()
 
-	s := db.NewFileSet("test", ldb)
+	s := db.NewFileSet("test)", fs.NewFilesystem(fs.FilesystemTypeBasic, "."), ldb)
 
 	// The Index ID for some random device is zero by default.
 	id := s.IndexID(remoteDevice0)

lib/fs/basicfs.go

@@ -9,30 +9,156 @@ package fs
 import (
 	"errors"
 	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
 	"time"
+
+	"github.com/calmh/du"
+)
+
+var (
+	ErrInvalidFilename = errors.New("filename is invalid")
+	ErrNotRelative     = errors.New("not a relative path")
 )
 
 // The BasicFilesystem implements all aspects by delegating to package os.
+// All paths are relative to the root and cannot (should not) escape the root directory.
 type BasicFilesystem struct {
+	root string
 }
 
-func NewBasicFilesystem() *BasicFilesystem {
-	return new(BasicFilesystem)
+func newBasicFilesystem(root string) *BasicFilesystem {
+	// The reason it's done like this:
+	// C:          ->  C:\            ->  C:\        (issue that this is trying to fix)
+	// C:\somedir  ->  C:\somedir\    ->  C:\somedir
+	// C:\somedir\ ->  C:\somedir\\   ->  C:\somedir
+	// This way in the tests, we get away without OS specific separators
+	// in the test configs.
+	root = filepath.Dir(root + string(filepath.Separator))
+
+	// Attempt tilde expansion; leave unchanged in case of error
+	if path, err := ExpandTilde(root); err == nil {
+		root = path
+	}
+
+	// Attempt absolutification; leave unchanged in case of error
+	if !filepath.IsAbs(root) {
+		// Abs() looks like a fairly expensive syscall on Windows, while
+		// IsAbs() is a whole bunch of string mangling. I think IsAbs() may be
+		// somewhat faster in the general case, hence the outer if...
+		if path, err := filepath.Abs(root); err == nil {
+			root = path
+		}
+	}
+
+	// Attempt to enable long filename support on Windows. We may still not
+	// have an absolute path here if the previous steps failed.
+	if runtime.GOOS == "windows" {
+		if filepath.IsAbs(root) && !strings.HasPrefix(root, `\\`) {
+			root = `\\?\` + root
+		}
+		// If we're not on Windows, we want the path to end with a slash to
+		// penetrate symlinks. On Windows, paths must not end with a slash.
+	} else if root[len(root)-1] != filepath.Separator {
+		root = root + string(filepath.Separator)
+	}
+
+	return &BasicFilesystem{
+		root: root,
+	}
+}
+
+// rooted expands the relative path to the full path that is then used with os
+// package. If the relative path somehow causes the final path to escape the root
+// directoy, this returns an error, to prevent accessing files that are not in the
+// shared directory.
+func (f *BasicFilesystem) rooted(rel string) (string, error) {
+	// The root must not be empty.
+	if f.root == "" {
+		return "", ErrInvalidFilename
+	}
+
+	pathSep := string(PathSeparator)
+
+	// The expected prefix for the resulting path is the root, with a path
+	// separator at the end.
+	expectedPrefix := filepath.FromSlash(f.root)
+	if !strings.HasSuffix(expectedPrefix, pathSep) {
+		expectedPrefix += pathSep
+	}
+
+	// The relative path should be clean from internal dotdots and similar
+	// funkyness.
+	rel = filepath.FromSlash(rel)
+	if filepath.Clean(rel) != rel {
+		return "", ErrInvalidFilename
+	}
+
+	// It is not acceptable to attempt to traverse upwards.
+	switch rel {
+	case "..", pathSep:
+		return "", ErrNotRelative
+	}
+	if strings.HasPrefix(rel, ".."+pathSep) {
+		return "", ErrNotRelative
+	}
+
+	if strings.HasPrefix(rel, pathSep+pathSep) {
+		// The relative path may pretend to be an absolute path within the
+		// root, but the double path separator on Windows implies something
+		// else. It would get cleaned by the Join below, but it's out of
+		// spec anyway.
+		return "", ErrNotRelative
+	}
+
+	// The supposedly correct path is the one filepath.Join will return, as
+	// it does cleaning and so on. Check that one first to make sure no
+	// obvious escape attempts have been made.
+	joined := filepath.Join(f.root, rel)
+	if rel == "." && !strings.HasSuffix(joined, pathSep) {
+		joined += pathSep
+	}
+	if !strings.HasPrefix(joined, expectedPrefix) {
+		return "", ErrNotRelative
+	}
+
+	return joined, nil
+}
+
+func (f *BasicFilesystem) unrooted(path string) string {
+	return strings.TrimPrefix(strings.TrimPrefix(path, f.root), string(PathSeparator))
 }
 
 func (f *BasicFilesystem) Chmod(name string, mode FileMode) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
 	return os.Chmod(name, os.FileMode(mode))
 }
 
 func (f *BasicFilesystem) Chtimes(name string, atime time.Time, mtime time.Time) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
 	return os.Chtimes(name, atime, mtime)
 }
 
 func (f *BasicFilesystem) Mkdir(name string, perm FileMode) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
 	return os.Mkdir(name, os.FileMode(perm))
 }
 
 func (f *BasicFilesystem) Lstat(name string) (FileInfo, error) {
+	name, err := f.rooted(name)
+	if err != nil {
+		return nil, err
+	}
 	fi, err := underlyingLstat(name)
 	if err != nil {
 		return nil, err
@@ -41,14 +167,38 @@ func (f *BasicFilesystem) Lstat(name string) (FileInfo, error) {
 }
 
 func (f *BasicFilesystem) Remove(name string) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
 	return os.Remove(name)
 }
 
+func (f *BasicFilesystem) RemoveAll(name string) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
+	return os.RemoveAll(name)
+}
+
 func (f *BasicFilesystem) Rename(oldpath, newpath string) error {
+	oldpath, err := f.rooted(oldpath)
+	if err != nil {
+		return err
+	}
+	newpath, err = f.rooted(newpath)
+	if err != nil {
+		return err
+	}
 	return os.Rename(oldpath, newpath)
 }
 
 func (f *BasicFilesystem) Stat(name string) (FileInfo, error) {
+	name, err := f.rooted(name)
+	if err != nil {
+		return nil, err
+	}
 	fi, err := os.Stat(name)
 	if err != nil {
 		return nil, err
@@ -57,7 +207,11 @@ func (f *BasicFilesystem) Stat(name string) (FileInfo, error) {
 }
 
 func (f *BasicFilesystem) DirNames(name string) ([]string, error) {
-	fd, err := os.OpenFile(name, os.O_RDONLY, 0777)
+	name, err := f.rooted(name)
+	if err != nil {
+		return nil, err
+	}
+	fd, err := os.OpenFile(name, OptReadOnly, 0777)
 	if err != nil {
 		return nil, err
 	}
@@ -72,19 +226,39 @@ func (f *BasicFilesystem) DirNames(name string) ([]string, error) {
 }
 
 func (f *BasicFilesystem) Open(name string) (File, error) {
-	fd, err := os.Open(name)
+	rootedName, err := f.rooted(name)
 	if err != nil {
 		return nil, err
 	}
-	return fsFile{fd}, err
+	fd, err := os.Open(rootedName)
+	if err != nil {
+		return nil, err
+	}
+	return fsFile{fd, name}, err
+}
+
+func (f *BasicFilesystem) OpenFile(name string, flags int, mode FileMode) (File, error) {
+	rootedName, err := f.rooted(name)
+	if err != nil {
+		return nil, err
+	}
+	fd, err := os.OpenFile(rootedName, flags, os.FileMode(mode))
+	if err != nil {
+		return nil, err
+	}
+	return fsFile{fd, name}, err
 }
 
 func (f *BasicFilesystem) Create(name string) (File, error) {
-	fd, err := os.Create(name)
+	rootedName, err := f.rooted(name)
 	if err != nil {
 		return nil, err
 	}
-	return fsFile{fd}, err
+	fd, err := os.Create(rootedName)
+	if err != nil {
+		return nil, err
+	}
+	return fsFile{fd, name}, err
 }
 
 func (f *BasicFilesystem) Walk(root string, walkFn WalkFunc) error {
@@ -92,9 +266,47 @@ func (f *BasicFilesystem) Walk(root string, walkFn WalkFunc) error {
 	return errors.New("not implemented")
 }
 
+func (f *BasicFilesystem) Glob(pattern string) ([]string, error) {
+	pattern, err := f.rooted(pattern)
+	if err != nil {
+		return nil, err
+	}
+	files, err := filepath.Glob(pattern)
+	unrooted := make([]string, len(files))
+	for i := range files {
+		unrooted[i] = f.unrooted(files[i])
+	}
+	return unrooted, err
+}
+
+func (f *BasicFilesystem) Usage(name string) (Usage, error) {
+	name, err := f.rooted(name)
+	if err != nil {
+		return Usage{}, err
+	}
+	u, err := du.Get(name)
+	return Usage{
+		Free:  u.FreeBytes,
+		Total: u.TotalBytes,
+	}, err
+}
+
+func (f *BasicFilesystem) Type() FilesystemType {
+	return FilesystemTypeBasic
+}
+
+func (f *BasicFilesystem) URI() string {
+	return strings.TrimPrefix(f.root, `\\?\`)
+}
+
 // fsFile implements the fs.File interface on top of an os.File
 type fsFile struct {
 	*os.File
+	name string
+}
+
+func (f fsFile) Name() string {
+	return f.name
 }
 
 func (f fsFile) Stat() (FileInfo, error) {
@@ -105,6 +317,17 @@ func (f fsFile) Stat() (FileInfo, error) {
 	return fsFileInfo{info}, nil
 }
 
+func (f fsFile) Sync() error {
+	err := f.File.Sync()
+	// On Windows, fsyncing a directory returns a "handle is invalid"
+	// So we swallow that and let things go through in order not to have to add
+	// a separate way of syncing directories versus files.
+	if err != nil && (runtime.GOOS != "windows" || !strings.Contains(err.Error(), "handle is invalid")) {
+		return err
+	}
+	return nil
+}
+
 // fsFileInfo implements the fs.FileInfo interface on top of an os.FileInfo.
 type fsFileInfo struct {
 	os.FileInfo

lib/fs/basicfs_symlink_unix.go

@@ -1,29 +0,0 @@
-// Copyright (C) 2016 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build !windows
-
-package fs
-
-import "os"
-
-var symlinksSupported = true
-
-func DisableSymlinks() {
-	symlinksSupported = false
-}
-
-func (BasicFilesystem) SymlinksSupported() bool {
-	return symlinksSupported
-}
-
-func (BasicFilesystem) CreateSymlink(name, target string) error {
-	return os.Symlink(target, name)
-}
-
-func (BasicFilesystem) ReadSymlink(path string) (string, error) {
-	return os.Readlink(path)
-}

lib/fs/basicfs_symlink_windows.go

@@ -1,27 +0,0 @@
-// Copyright (C) 2014 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build windows
-
-package fs
-
-import "errors"
-
-var errNotSupported = errors.New("symlinks not supported")
-
-func DisableSymlinks() {}
-
-func (BasicFilesystem) SymlinksSupported() bool {
-	return false
-}
-
-func (BasicFilesystem) ReadSymlink(path string) (string, error) {
-	return "", errNotSupported
-}
-
-func (BasicFilesystem) CreateSymlink(path, target string) error {
-	return errNotSupported
-}

lib/fs/basicfs_test.go

@@ -0,0 +1,486 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strings"
+	"testing"
+	"time"
+)
+
+func setup(t *testing.T) (Filesystem, string) {
+	dir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	return newBasicFilesystem(dir), dir
+}
+
+func TestChmodFile(t *testing.T) {
+	fs, dir := setup(t)
+	path := filepath.Join(dir, "file")
+	defer os.RemoveAll(dir)
+
+	defer os.Chmod(path, 0666)
+
+	fd, err := os.Create(path)
+	if err != nil {
+		t.Error(err)
+	}
+	fd.Close()
+
+	if err := os.Chmod(path, 0666); err != nil {
+		t.Error(err)
+	}
+
+	if stat, err := os.Stat(path); err != nil || stat.Mode()&os.ModePerm != 0666 {
+		t.Errorf("wrong perm: %t %#o", err == nil, stat.Mode()&os.ModePerm)
+	}
+
+	if err := fs.Chmod("file", 0444); err != nil {
+		t.Error(err)
+	}
+
+	if stat, err := os.Stat(path); err != nil || stat.Mode()&os.ModePerm != 0444 {
+		t.Errorf("wrong perm: %t %#o", err == nil, stat.Mode()&os.ModePerm)
+	}
+}
+
+func TestChmodDir(t *testing.T) {
+	fs, dir := setup(t)
+	path := filepath.Join(dir, "dir")
+	defer os.RemoveAll(dir)
+
+	mode := os.FileMode(0755)
+	if runtime.GOOS == "windows" {
+		mode = os.FileMode(0777)
+	}
+
+	defer os.Chmod(path, mode)
+
+	if err := os.Mkdir(path, mode); err != nil {
+		t.Error(err)
+	}
+
+	if stat, err := os.Stat(path); err != nil || stat.Mode()&os.ModePerm != mode {
+		t.Errorf("wrong perm: %t %#o", err == nil, stat.Mode()&os.ModePerm)
+	}
+
+	if err := fs.Chmod("dir", 0555); err != nil {
+		t.Error(err)
+	}
+
+	if stat, err := os.Stat(path); err != nil || stat.Mode()&os.ModePerm != 0555 {
+		t.Errorf("wrong perm: %t %#o", err == nil, stat.Mode()&os.ModePerm)
+	}
+}
+
+func TestChtimes(t *testing.T) {
+	fs, dir := setup(t)
+	path := filepath.Join(dir, "file")
+	defer os.RemoveAll(dir)
+	fd, err := os.Create(path)
+	if err != nil {
+		t.Error(err)
+	}
+	fd.Close()
+
+	mtime := time.Now().Add(-time.Hour)
+
+	fs.Chtimes("file", mtime, mtime)
+
+	stat, err := os.Stat(path)
+	if err != nil {
+		t.Error(err)
+	}
+
+	diff := stat.ModTime().Sub(mtime)
+	if diff > 3*time.Second || diff < -3*time.Second {
+		t.Errorf("%s != %s", stat.Mode(), mtime)
+	}
+}
+
+func TestCreate(t *testing.T) {
+	fs, dir := setup(t)
+	path := filepath.Join(dir, "file")
+	defer os.RemoveAll(dir)
+
+	if _, err := os.Stat(path); err == nil {
+		t.Errorf("exists?")
+	}
+
+	fd, err := fs.Create("file")
+	if err != nil {
+		t.Error(err)
+	}
+	fd.Close()
+
+	if _, err := os.Stat(path); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestCreateSymlink(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("windows not supported")
+	}
+
+	fs, dir := setup(t)
+	path := filepath.Join(dir, "file")
+	defer os.RemoveAll(dir)
+
+	if err := fs.CreateSymlink("blah", "file"); err != nil {
+		t.Error(err)
+	}
+
+	if target, err := os.Readlink(path); err != nil || target != "blah" {
+		t.Error("target", target, "err", err)
+	}
+
+	if err := os.Remove(path); err != nil {
+		t.Error(err)
+	}
+
+	if err := fs.CreateSymlink(filepath.Join("..", "blah"), "file"); err != nil {
+		t.Error(err)
+	}
+
+	if target, err := os.Readlink(path); err != nil || target != filepath.Join("..", "blah") {
+		t.Error("target", target, "err", err)
+	}
+}
+
+func TestDirNames(t *testing.T) {
+	fs, dir := setup(t)
+	defer os.RemoveAll(dir)
+
+	// Case differences
+	testCases := []string{
+		"a",
+		"bC",
+	}
+	sort.Strings(testCases)
+
+	for _, sub := range testCases {
+		if err := os.Mkdir(filepath.Join(dir, sub), 0777); err != nil {
+			t.Error(err)
+		}
+	}
+
+	if dirs, err := fs.DirNames("."); err != nil || len(dirs) != len(testCases) {
+		t.Errorf("%s %s %s", err, dirs, testCases)
+	} else {
+		sort.Strings(dirs)
+		for i := range dirs {
+			if dirs[i] != testCases[i] {
+				t.Errorf("%s != %s", dirs[i], testCases[i])
+			}
+		}
+	}
+}
+
+func TestNames(t *testing.T) {
+	// Tests that all names are without the root directory.
+	fs, dir := setup(t)
+	defer os.RemoveAll(dir)
+
+	expected := "file"
+	fd, err := fs.Create(expected)
+	if err != nil {
+		t.Error(err)
+	}
+	defer fd.Close()
+
+	if fd.Name() != expected {
+		t.Errorf("incorrect %s != %s", fd.Name(), expected)
+	}
+	if stat, err := fd.Stat(); err != nil || stat.Name() != expected {
+		t.Errorf("incorrect %s != %s (%v)", stat.Name(), expected, err)
+	}
+
+	if err := fs.Mkdir("dir", 0777); err != nil {
+		t.Error(err)
+	}
+
+	expected = filepath.Join("dir", "file")
+	fd, err = fs.Create(expected)
+	if err != nil {
+		t.Error(err)
+	}
+	defer fd.Close()
+
+	if fd.Name() != expected {
+		t.Errorf("incorrect %s != %s", fd.Name(), expected)
+	}
+
+	// os.fd.Stat() returns just base, so do we.
+	if stat, err := fd.Stat(); err != nil || stat.Name() != filepath.Base(expected) {
+		t.Errorf("incorrect %s != %s (%v)", stat.Name(), filepath.Base(expected), err)
+	}
+}
+
+func TestGlob(t *testing.T) {
+	// Tests that all names are without the root directory.
+	fs, dir := setup(t)
+	defer os.RemoveAll(dir)
+
+	for _, dirToCreate := range []string{
+		filepath.Join("a", "test", "b"),
+		filepath.Join("a", "best", "b"),
+		filepath.Join("a", "best", "c"),
+	} {
+		if err := fs.MkdirAll(dirToCreate, 0777); err != nil {
+			t.Error(err)
+		}
+	}
+
+	testCases := []struct {
+		pattern string
+		matches []string
+	}{
+		{
+			filepath.Join("a", "?est", "?"),
+			[]string{
+				filepath.Join("a", "test", "b"),
+				filepath.Join("a", "best", "b"),
+				filepath.Join("a", "best", "c"),
+			},
+		},
+		{
+			filepath.Join("a", "?est", "b"),
+			[]string{
+				filepath.Join("a", "test", "b"),
+				filepath.Join("a", "best", "b"),
+			},
+		},
+		{
+			filepath.Join("a", "best", "?"),
+			[]string{
+				filepath.Join("a", "best", "b"),
+				filepath.Join("a", "best", "c"),
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+		results, err := fs.Glob(testCase.pattern)
+		sort.Strings(results)
+		sort.Strings(testCase.matches)
+		if err != nil {
+			t.Error(err)
+		}
+		if len(results) != len(testCase.matches) {
+			t.Errorf("result count mismatch")
+		}
+		for i := range testCase.matches {
+			if results[i] != testCase.matches[i] {
+				t.Errorf("%s != %s", results[i], testCase.matches[i])
+			}
+		}
+	}
+}
+
+func TestUsage(t *testing.T) {
+	fs, dir := setup(t)
+	defer os.RemoveAll(dir)
+	usage, err := fs.Usage(".")
+	if err != nil {
+		if runtime.GOOS == "netbsd" || runtime.GOOS == "openbsd" || runtime.GOOS == "solaris" {
+			t.Skip()
+		}
+		t.Errorf("Unexpected error: %s", err)
+	}
+	if usage.Free < 1 {
+		t.Error("Disk is full?", usage.Free)
+	}
+}
+
+func TestWindowsPaths(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skip("Not useful on non-Windows")
+		return
+	}
+
+	testCases := []struct {
+		input        string
+		expectedRoot string
+		expectedURI  string
+	}{
+		{`e:\`, `\\?\e:\`, `e:\`},
+		{`\\?\e:\`, `\\?\e:\`, `e:\`},
+		{`\\192.0.2.22\network\share`, `\\192.0.2.22\network\share`, `\\192.0.2.22\network\share`},
+	}
+
+	for _, testCase := range testCases {
+		fs := newBasicFilesystem(testCase.input)
+		if fs.root != testCase.expectedRoot {
+			t.Errorf("root %q != %q", fs.root, testCase.expectedRoot)
+		}
+		if fs.URI() != testCase.expectedURI {
+			t.Errorf("uri %q != %q", fs.URI(), testCase.expectedURI)
+		}
+	}
+
+	fs := newBasicFilesystem(`relative\path`)
+	if fs.root == `relative\path` || !strings.HasPrefix(fs.root, "\\\\?\\") {
+		t.Errorf("%q == %q, expected absolutification", fs.root, `relative\path`)
+	}
+}
+
+func TestRooted(t *testing.T) {
+	type testcase struct {
+		root   string
+		rel    string
+		joined string
+		ok     bool
+	}
+	cases := []testcase{
+		// Valid cases
+		{"foo", "bar", "foo/bar", true},
+		{"foo", "/bar", "foo/bar", true},
+		{"foo/", "bar", "foo/bar", true},
+		{"foo/", "/bar", "foo/bar", true},
+		{"baz/foo", "bar", "baz/foo/bar", true},
+		{"baz/foo", "/bar", "baz/foo/bar", true},
+		{"baz/foo/", "bar", "baz/foo/bar", true},
+		{"baz/foo/", "/bar", "baz/foo/bar", true},
+		{"foo", "bar/baz", "foo/bar/baz", true},
+		{"foo", "/bar/baz", "foo/bar/baz", true},
+		{"foo/", "bar/baz", "foo/bar/baz", true},
+		{"foo/", "/bar/baz", "foo/bar/baz", true},
+		{"baz/foo", "bar/baz", "baz/foo/bar/baz", true},
+		{"baz/foo", "/bar/baz", "baz/foo/bar/baz", true},
+		{"baz/foo/", "bar/baz", "baz/foo/bar/baz", true},
+		{"baz/foo/", "/bar/baz", "baz/foo/bar/baz", true},
+
+		// Not escape attempts, but oddly formatted relative paths. Disallowed.
+		{"foo", "./bar", "", false},
+		{"baz/foo", "./bar", "", false},
+		{"foo", "./bar/baz", "", false},
+		{"baz/foo", "./bar/baz", "", false},
+		{"baz/foo", "bar/../baz", "", false},
+		{"baz/foo", "/bar/../baz", "", false},
+		{"baz/foo", "./bar/../baz", "", false},
+		{"baz/foo", "bar/../baz", "", false},
+		{"baz/foo", "/bar/../baz", "", false},
+		{"baz/foo", "./bar/../baz", "", false},
+
+		// Results in an allowed path, but does it by probing. Disallowed.
+		{"foo", "../foo", "", false},
+		{"foo", "../foo/bar", "", false},
+		{"baz/foo", "../foo/bar", "", false},
+		{"baz/foo", "../../baz/foo/bar", "", false},
+		{"baz/foo", "bar/../../foo/bar", "", false},
+		{"baz/foo", "bar/../../../baz/foo/bar", "", false},
+
+		// Escape attempts.
+		{"foo", "", "", false},
+		{"foo", "/", "", false},
+		{"foo", "..", "", false},
+		{"foo", "/..", "", false},
+		{"foo", "../", "", false},
+		{"foo", "../bar", "", false},
+		{"foo", "../foobar", "", false},
+		{"foo/", "../bar", "", false},
+		{"foo/", "../foobar", "", false},
+		{"baz/foo", "../bar", "", false},
+		{"baz/foo", "../foobar", "", false},
+		{"baz/foo/", "../bar", "", false},
+		{"baz/foo/", "../foobar", "", false},
+		{"baz/foo/", "bar/../../quux/baz", "", false},
+
+		// Empty root is a misconfiguration.
+		{"", "/foo", "", false},
+		{"", "foo", "", false},
+		{"", ".", "", false},
+		{"", "..", "", false},
+		{"", "/", "", false},
+		{"", "", "", false},
+
+		// Root=/ is valid, and things should be verified as usual.
+		{"/", "foo", "/foo", true},
+		{"/", "/foo", "/foo", true},
+		{"/", "../foo", "", false},
+		{"/", "..", "", false},
+		{"/", "/", "", false},
+		{"/", "", "", false},
+
+		// special case for filesystems to be able to MkdirAll('.') for example
+		{"/", ".", "/", true},
+	}
+
+	if runtime.GOOS == "windows" {
+		extraCases := []testcase{
+			{`c:\`, `foo`, `c:\foo`, true},
+			{`\\?\c:\`, `foo`, `\\?\c:\foo`, true},
+			{`c:\`, `\foo`, `c:\foo`, true},
+			{`\\?\c:\`, `\foo`, `\\?\c:\foo`, true},
+			{`c:\`, `\\foo`, ``, false},
+			{`c:\`, ``, ``, false},
+			{`c:\`, `\`, ``, false},
+			{`\\?\c:\`, `\\foo`, ``, false},
+			{`\\?\c:\`, ``, ``, false},
+			{`\\?\c:\`, `\`, ``, false},
+
+			// makes no sense, but will be treated simply as a bad filename
+			{`c:\foo`, `d:\bar`, `c:\foo\d:\bar`, true},
+
+			// special case for filesystems to be able to MkdirAll('.') for example
+			{`c:\`, `.`, `c:\`, true},
+			{`\\?\c:\`, `.`, `\\?\c:\`, true},
+		}
+
+		for _, tc := range cases {
+			// Add case where root is backslashed, rel is forward slashed
+			extraCases = append(extraCases, testcase{
+				root:   filepath.FromSlash(tc.root),
+				rel:    tc.rel,
+				joined: tc.joined,
+				ok:     tc.ok,
+			})
+			// and the opposite
+			extraCases = append(extraCases, testcase{
+				root:   tc.root,
+				rel:    filepath.FromSlash(tc.rel),
+				joined: tc.joined,
+				ok:     tc.ok,
+			})
+			// and both backslashed
+			extraCases = append(extraCases, testcase{
+				root:   filepath.FromSlash(tc.root),
+				rel:    filepath.FromSlash(tc.rel),
+				joined: tc.joined,
+				ok:     tc.ok,
+			})
+		}
+
+		cases = append(cases, extraCases...)
+	}
+
+	for _, tc := range cases {
+		fs := BasicFilesystem{root: tc.root}
+		res, err := fs.rooted(tc.rel)
+		if tc.ok {
+			if err != nil {
+				t.Errorf("Unexpected error for rooted(%q, %q): %v", tc.root, tc.rel, err)
+				continue
+			}
+			exp := filepath.FromSlash(tc.joined)
+			if res != exp {
+				t.Errorf("Unexpected result for rooted(%q, %q): %q != expected %q", tc.root, tc.rel, res, exp)
+			}
+		} else if err == nil {
+			t.Errorf("Unexpected pass for rooted(%q, %q) => %q", tc.root, tc.rel, res)
+			continue
+		}
+	}
+}

lib/fs/basicfs_unix.go

@@ -0,0 +1,57 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+// +build !windows
+
+package fs
+
+import "os"
+
+func (BasicFilesystem) SymlinksSupported() bool {
+	return true
+}
+
+func (f *BasicFilesystem) CreateSymlink(target, name string) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
+	return os.Symlink(target, name)
+}
+
+func (f *BasicFilesystem) ReadSymlink(name string) (string, error) {
+	name, err := f.rooted(name)
+	if err != nil {
+		return "", err
+	}
+	return os.Readlink(name)
+}
+
+func (f *BasicFilesystem) MkdirAll(name string, perm FileMode) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
+	return os.MkdirAll(name, os.FileMode(perm))
+}
+
+// Unhide is a noop on unix, as unhiding files requires renaming them.
+// We still check that the relative path does not try to escape the root
+func (f *BasicFilesystem) Unhide(name string) error {
+	_, err := f.rooted(name)
+	return err
+}
+
+// Hide is a noop on unix, as hiding files requires renaming them.
+// We still check that the relative path does not try to escape the root
+func (f *BasicFilesystem) Hide(name string) error {
+	_, err := f.rooted(name)
+	return err
+}
+
+func (f *BasicFilesystem) Roots() ([]string, error) {
+	return []string{"/"}, nil
+}

lib/fs/basicfs_windows.go

@@ -0,0 +1,165 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+// +build windows
+
+package fs
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+	"unsafe"
+)
+
+var errNotSupported = errors.New("symlinks not supported")
+
+func (BasicFilesystem) SymlinksSupported() bool {
+	return false
+}
+
+func (BasicFilesystem) ReadSymlink(path string) (string, error) {
+	return "", errNotSupported
+}
+
+func (BasicFilesystem) CreateSymlink(path, target string) error {
+	return errNotSupported
+}
+
+// MkdirAll creates a directory named path, along with any necessary parents,
+// and returns nil, or else returns an error.
+// The permission bits perm are used for all directories that MkdirAll creates.
+// If path is already a directory, MkdirAll does nothing and returns nil.
+func (f *BasicFilesystem) MkdirAll(path string, perm FileMode) error {
+	path, err := f.rooted(path)
+	if err != nil {
+		return err
+	}
+
+	return f.mkdirAll(path, os.FileMode(perm))
+}
+
+// Required due to https://github.com/golang/go/issues/10900
+func (f *BasicFilesystem) mkdirAll(path string, perm os.FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &os.PathError{
+			Op:   "mkdir",
+			Path: path,
+			Err:  syscall.ENOTDIR,
+		}
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+
+	j := i
+	for j > 0 && !IsPathSeparator(path[j-1]) { // Scan backward over element.
+		j--
+	}
+
+	if j > 1 {
+		// Create parent
+		parent := path[0 : j-1]
+		if parent != filepath.VolumeName(parent) {
+			err = os.MkdirAll(parent, perm)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}
+
+func (f *BasicFilesystem) Unhide(name string) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
+	p, err := syscall.UTF16PtrFromString(name)
+	if err != nil {
+		return err
+	}
+
+	attrs, err := syscall.GetFileAttributes(p)
+	if err != nil {
+		return err
+	}
+
+	attrs &^= syscall.FILE_ATTRIBUTE_HIDDEN
+	return syscall.SetFileAttributes(p, attrs)
+}
+
+func (f *BasicFilesystem) Hide(name string) error {
+	name, err := f.rooted(name)
+	if err != nil {
+		return err
+	}
+	p, err := syscall.UTF16PtrFromString(name)
+	if err != nil {
+		return err
+	}
+
+	attrs, err := syscall.GetFileAttributes(p)
+	if err != nil {
+		return err
+	}
+
+	attrs |= syscall.FILE_ATTRIBUTE_HIDDEN
+	return syscall.SetFileAttributes(p, attrs)
+}
+
+func (f *BasicFilesystem) Roots() ([]string, error) {
+	kernel32, err := syscall.LoadDLL("kernel32.dll")
+	if err != nil {
+		return nil, err
+	}
+	getLogicalDriveStringsHandle, err := kernel32.FindProc("GetLogicalDriveStringsA")
+	if err != nil {
+		return nil, err
+	}
+
+	buffer := [1024]byte{}
+	bufferSize := uint32(len(buffer))
+
+	hr, _, _ := getLogicalDriveStringsHandle.Call(uintptr(unsafe.Pointer(&bufferSize)), uintptr(unsafe.Pointer(&buffer)))
+	if hr == 0 {
+		return nil, fmt.Errorf("Syscall failed")
+	}
+
+	var drives []string
+	parts := bytes.Split(buffer[:], []byte{0})
+	for _, part := range parts {
+		if len(part) == 0 {
+			break
+		}
+		drives = append(drives, string(part))
+	}
+
+	return drives, nil
+}

lib/fs/debug.go

@@ -0,0 +1,22 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"os"
+	"strings"
+
+	"github.com/syncthing/syncthing/lib/logger"
+)
+
+var (
+	l = logger.DefaultLogger.NewFacility("filesystem", "Filesystem access")
+)
+
+func init() {
+	l.SetDebug("filesystem", strings.Contains(os.Getenv("STTRACE"), "filesystem") || os.Getenv("STTRACE") == "all")
+}

lib/fs/errorfs.go

@@ -0,0 +1,41 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import "time"
+
+type errorFilesystem struct {
+	err    error
+	fsType FilesystemType
+	uri    string
+}
+
+func (fs *errorFilesystem) Chmod(name string, mode FileMode) error                      { return fs.err }
+func (fs *errorFilesystem) Chtimes(name string, atime time.Time, mtime time.Time) error { return fs.err }
+func (fs *errorFilesystem) Create(name string) (File, error)                            { return nil, fs.err }
+func (fs *errorFilesystem) CreateSymlink(name, target string) error                     { return fs.err }
+func (fs *errorFilesystem) DirNames(name string) ([]string, error)                      { return nil, fs.err }
+func (fs *errorFilesystem) Lstat(name string) (FileInfo, error)                         { return nil, fs.err }
+func (fs *errorFilesystem) Mkdir(name string, perm FileMode) error                      { return fs.err }
+func (fs *errorFilesystem) MkdirAll(name string, perm FileMode) error                   { return fs.err }
+func (fs *errorFilesystem) Open(name string) (File, error)                              { return nil, fs.err }
+func (fs *errorFilesystem) OpenFile(string, int, FileMode) (File, error)                { return nil, fs.err }
+func (fs *errorFilesystem) ReadSymlink(name string) (string, error)                     { return "", fs.err }
+func (fs *errorFilesystem) Remove(name string) error                                    { return fs.err }
+func (fs *errorFilesystem) RemoveAll(name string) error                                 { return fs.err }
+func (fs *errorFilesystem) Rename(oldname, newname string) error                        { return fs.err }
+func (fs *errorFilesystem) Stat(name string) (FileInfo, error)                          { return nil, fs.err }
+func (fs *errorFilesystem) SymlinksSupported() bool                                     { return false }
+func (fs *errorFilesystem) Walk(root string, walkFn WalkFunc) error                     { return fs.err }
+func (fs *errorFilesystem) Unhide(name string) error                                    { return fs.err }
+func (fs *errorFilesystem) Hide(name string) error                                      { return fs.err }
+func (fs *errorFilesystem) Glob(pattern string) ([]string, error)                       { return nil, fs.err }
+func (fs *errorFilesystem) SyncDir(name string) error                                   { return fs.err }
+func (fs *errorFilesystem) Roots() ([]string, error)                                    { return nil, fs.err }
+func (fs *errorFilesystem) Usage(name string) (Usage, error)                            { return Usage{}, fs.err }
+func (fs *errorFilesystem) Type() FilesystemType                                        { return fs.fsType }
+func (fs *errorFilesystem) URI() string                                                 { return fs.uri }

lib/fs/filesystem.go

@@ -7,6 +7,7 @@
 package fs
 
 import (
+	"errors"
 	"io"
 	"os"
 	"path/filepath"
@@ -22,23 +23,38 @@ type Filesystem interface {
 	DirNames(name string) ([]string, error)
 	Lstat(name string) (FileInfo, error)
 	Mkdir(name string, perm FileMode) error
+	MkdirAll(name string, perm FileMode) error
 	Open(name string) (File, error)
+	OpenFile(name string, flags int, mode FileMode) (File, error)
 	ReadSymlink(name string) (string, error)
 	Remove(name string) error
+	RemoveAll(name string) error
 	Rename(oldname, newname string) error
 	Stat(name string) (FileInfo, error)
 	SymlinksSupported() bool
 	Walk(root string, walkFn WalkFunc) error
+	Hide(name string) error
+	Unhide(name string) error
+	Glob(pattern string) ([]string, error)
+	Roots() ([]string, error)
+	Usage(name string) (Usage, error)
+	Type() FilesystemType
+	URI() string
 }
 
 // The File interface abstracts access to a regular file, being a somewhat
 // smaller interface than os.File
 type File interface {
-	io.Reader
-	io.WriterAt
 	io.Closer
+	io.Reader
+	io.ReaderAt
+	io.Seeker
+	io.Writer
+	io.WriterAt
+	Name() string
 	Truncate(size int64) error
 	Stat() (FileInfo, error)
+	Sync() error
 }
 
 // The FileInfo interface is almost the same as os.FileInfo, but with the
@@ -59,12 +75,27 @@ type FileInfo interface {
 // FileMode is similar to os.FileMode
 type FileMode uint32
 
-// ModePerm is the equivalent of os.ModePerm
-const ModePerm = FileMode(os.ModePerm)
+// Usage represents filesystem space usage
+type Usage struct {
+	Free  int64
+	Total int64
+}
 
-// DefaultFilesystem is the fallback to use when nothing explicitly has
-// been passed.
-var DefaultFilesystem Filesystem = NewWalkFilesystem(NewBasicFilesystem())
+// Equivalents from os package.
+
+const ModePerm = FileMode(os.ModePerm)
+const ModeSetgid = FileMode(os.ModeSetgid)
+const ModeSetuid = FileMode(os.ModeSetuid)
+const ModeSticky = FileMode(os.ModeSticky)
+const PathSeparator = os.PathSeparator
+const OptAppend = os.O_APPEND
+const OptCreate = os.O_CREATE
+const OptExclusive = os.O_EXCL
+const OptReadOnly = os.O_RDONLY
+const OptReadWrite = os.O_RDWR
+const OptSync = os.O_SYNC
+const OptTruncate = os.O_TRUNC
+const OptWriteOnly = os.O_WRONLY
 
 // SkipDir is used as a return value from WalkFuncs to indicate that
 // the directory named in the call is to be skipped. It is not returned
@@ -76,3 +107,29 @@ var IsExist = os.IsExist
 
 // IsNotExist is the equivalent of os.IsNotExist
 var IsNotExist = os.IsNotExist
+
+// IsPermission is the equivalent of os.IsPermission
+var IsPermission = os.IsPermission
+
+// IsPathSeparator is the equivalent of os.IsPathSeparator
+var IsPathSeparator = os.IsPathSeparator
+
+func NewFilesystem(fsType FilesystemType, uri string) Filesystem {
+	var fs Filesystem
+	switch fsType {
+	case FilesystemTypeBasic:
+		fs = NewWalkFilesystem(newBasicFilesystem(uri))
+	default:
+		l.Debugln("Unknown filesystem", fsType, uri)
+		fs = &errorFilesystem{
+			fsType: fsType,
+			uri:    uri,
+			err:    errors.New("filesystem with type " + fsType.String() + " does not exist."),
+		}
+	}
+
+	if l.ShouldDebug("filesystem") {
+		fs = &logFilesystem{fs}
+	}
+	return fs
+}

lib/fs/logfs.go

@@ -0,0 +1,158 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"time"
+)
+
+type logFilesystem struct {
+	Filesystem
+}
+
+func getCaller() string {
+	_, file, line, ok := runtime.Caller(2)
+	if !ok {
+		return "unknown"
+	}
+	return fmt.Sprintf("%s:%d", filepath.Base(file), line)
+}
+
+func (fs *logFilesystem) Chmod(name string, mode FileMode) error {
+	err := fs.Filesystem.Chmod(name, mode)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Chmod", name, mode, err)
+	return err
+}
+
+func (fs *logFilesystem) Chtimes(name string, atime time.Time, mtime time.Time) error {
+	err := fs.Filesystem.Chtimes(name, atime, mtime)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Chtimes", name, atime, mtime, err)
+	return err
+}
+
+func (fs *logFilesystem) Create(name string) (File, error) {
+	file, err := fs.Filesystem.Create(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Create", name, file, err)
+	return file, err
+}
+
+func (fs *logFilesystem) CreateSymlink(name, target string) error {
+	err := fs.Filesystem.CreateSymlink(name, target)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "CreateSymlink", name, target, err)
+	return err
+}
+
+func (fs *logFilesystem) DirNames(name string) ([]string, error) {
+	names, err := fs.Filesystem.DirNames(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "DirNames", name, names, err)
+	return names, err
+}
+
+func (fs *logFilesystem) Lstat(name string) (FileInfo, error) {
+	info, err := fs.Filesystem.Lstat(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Lstat", name, info, err)
+	return info, err
+}
+
+func (fs *logFilesystem) Mkdir(name string, perm FileMode) error {
+	err := fs.Filesystem.Mkdir(name, perm)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Mkdir", name, perm, err)
+	return err
+}
+
+func (fs *logFilesystem) MkdirAll(name string, perm FileMode) error {
+	err := fs.Filesystem.MkdirAll(name, perm)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "MkdirAll", name, perm, err)
+	return err
+}
+
+func (fs *logFilesystem) Open(name string) (File, error) {
+	file, err := fs.Filesystem.Open(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Open", name, file, err)
+	return file, err
+}
+
+func (fs *logFilesystem) OpenFile(name string, flags int, mode FileMode) (File, error) {
+	file, err := fs.Filesystem.OpenFile(name, flags, mode)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "OpenFile", name, flags, mode, file, err)
+	return file, err
+}
+
+func (fs *logFilesystem) ReadSymlink(name string) (string, error) {
+	target, err := fs.Filesystem.ReadSymlink(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "ReadSymlink", name, target, err)
+	return target, err
+}
+
+func (fs *logFilesystem) Remove(name string) error {
+	err := fs.Filesystem.Remove(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Remove", name, err)
+	return err
+}
+
+func (fs *logFilesystem) RemoveAll(name string) error {
+	err := fs.Filesystem.RemoveAll(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "RemoveAll", name, err)
+	return err
+}
+
+func (fs *logFilesystem) Rename(oldname, newname string) error {
+	err := fs.Filesystem.Rename(oldname, newname)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Rename", oldname, newname, err)
+	return err
+}
+
+func (fs *logFilesystem) Stat(name string) (FileInfo, error) {
+	info, err := fs.Filesystem.Stat(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Stat", name, info, err)
+	return info, err
+}
+
+func (fs *logFilesystem) SymlinksSupported() bool {
+	supported := fs.Filesystem.SymlinksSupported()
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "SymlinksSupported", supported)
+	return supported
+}
+
+func (fs *logFilesystem) Walk(root string, walkFn WalkFunc) error {
+	err := fs.Filesystem.Walk(root, walkFn)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Walk", root, walkFn, err)
+	return err
+}
+
+func (fs *logFilesystem) Unhide(name string) error {
+	err := fs.Filesystem.Unhide(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Unhide", name, err)
+	return err
+}
+
+func (fs *logFilesystem) Hide(name string) error {
+	err := fs.Filesystem.Hide(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Hide", name, err)
+	return err
+}
+
+func (fs *logFilesystem) Glob(name string) ([]string, error) {
+	names, err := fs.Filesystem.Glob(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Glob", name, names, err)
+	return names, err
+}
+
+func (fs *logFilesystem) Roots() ([]string, error) {
+	roots, err := fs.Filesystem.Roots()
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Roots", roots, err)
+	return roots, err
+}
+
+func (fs *logFilesystem) Usage(name string) (Usage, error) {
+	usage, err := fs.Filesystem.Usage(name)
+	l.Debugln(getCaller(), fs.Type(), fs.URI(), "Usage", name, usage, err)
+	return usage, err
+}

lib/fs/mtimefs.go

@@ -6,12 +6,7 @@
 
 package fs
 
-import (
-	"os"
-	"time"
-
-	"github.com/syncthing/syncthing/lib/osutil"
-)
+import "time"
 
 // The database is where we store the virtual mtimes
 type database interface {
@@ -20,36 +15,34 @@ type database interface {
 	Delete(key string)
 }
 
-// variable so that we can mock it for testing
-var osChtimes = os.Chtimes
-
 // The MtimeFS is a filesystem with nanosecond mtime precision, regardless
 // of what shenanigans the underlying filesystem gets up to. A nil MtimeFS
 // just does the underlying operations with no additions.
 type MtimeFS struct {
 	Filesystem
-	db database
+	chtimes func(string, time.Time, time.Time) error
+	db      database
 }
 
 func NewMtimeFS(underlying Filesystem, db database) *MtimeFS {
 	return &MtimeFS{
 		Filesystem: underlying,
+		chtimes:    underlying.Chtimes, // for mocking it out in the tests
 		db:         db,
 	}
 }
 
 func (f *MtimeFS) Chtimes(name string, atime, mtime time.Time) error {
 	if f == nil {
-		return osChtimes(name, atime, mtime)
+		return f.chtimes(name, atime, mtime)
 	}
 
 	// Do a normal Chtimes call, don't care if it succeeds or not.
-	osChtimes(name, atime, mtime)
+	f.chtimes(name, atime, mtime)
 
 	// Stat the file to see what happened. Here we *do* return an error,
-	// because it might be "does not exist" or similar. osutil.Lstat is the
-	// souped up version to account for Android breakage.
-	info, err := osutil.Lstat(name)
+	// because it might be "does not exist" or similar.
+	info, err := f.Filesystem.Lstat(name)
 	if err != nil {
 		return err
 	}

lib/fs/mtimefs_test.go

@@ -25,22 +25,22 @@ func TestMtimeFS(t *testing.T) {
 	// a random time with nanosecond precision
 	testTime := time.Unix(1234567890, 123456789)
 
-	mtimefs := NewMtimeFS(DefaultFilesystem, make(mapStore))
+	mtimefs := NewMtimeFS(newBasicFilesystem("."), make(mapStore))
 
 	// Do one Chtimes call that will go through to the normal filesystem
-	osChtimes = os.Chtimes
+	mtimefs.chtimes = os.Chtimes
 	if err := mtimefs.Chtimes("testdata/exists0", testTime, testTime); err != nil {
 		t.Error("Should not have failed:", err)
 	}
 
 	// Do one call that gets an error back from the underlying Chtimes
-	osChtimes = failChtimes
+	mtimefs.chtimes = failChtimes
 	if err := mtimefs.Chtimes("testdata/exists1", testTime, testTime); err != nil {
 		t.Error("Should not have failed:", err)
 	}
 
 	// Do one call that gets struck by an exceptionally evil Chtimes
-	osChtimes = evilChtimes
+	mtimefs.chtimes = evilChtimes
 	if err := mtimefs.Chtimes("testdata/exists2", testTime, testTime); err != nil {
 		t.Error("Should not have failed:", err)
 	}

lib/fs/types.go

@@ -0,0 +1,36 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+type FilesystemType int
+
+const (
+	FilesystemTypeBasic FilesystemType = iota // default is basic
+)
+
+func (t FilesystemType) String() string {
+	switch t {
+	case FilesystemTypeBasic:
+		return "basic"
+	default:
+		return "unknown"
+	}
+}
+
+func (t FilesystemType) MarshalText() ([]byte, error) {
+	return []byte(t.String()), nil
+}
+
+func (t *FilesystemType) UnmarshalText(bs []byte) error {
+	switch string(bs) {
+	case "basic":
+		*t = FilesystemTypeBasic
+	default:
+		*t = FilesystemTypeBasic
+	}
+	return nil
+}

lib/fs/util.go

@@ -0,0 +1,55 @@
+// Copyright (C) 2016 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package fs
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+var errNoHome = errors.New("no home directory found - set $HOME (or the platform equivalent)")
+
+func ExpandTilde(path string) (string, error) {
+	if path == "~" {
+		return getHomeDir()
+	}
+
+	path = filepath.FromSlash(path)
+	if !strings.HasPrefix(path, fmt.Sprintf("~%c", PathSeparator)) {
+		return path, nil
+	}
+
+	home, err := getHomeDir()
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(home, path[2:]), nil
+}
+
+func getHomeDir() (string, error) {
+	var home string
+
+	switch runtime.GOOS {
+	case "windows":
+		home = filepath.Join(os.Getenv("HomeDrive"), os.Getenv("HomePath"))
+		if home == "" {
+			home = os.Getenv("UserProfile")
+		}
+	default:
+		home = os.Getenv("HOME")
+	}
+
+	if home == "" {
+		return "", errNoHome
+	}
+
+	return home, nil
+}

lib/fs/walkfs.go

@@ -28,16 +28,16 @@ import "path/filepath"
 // Walk skips the remaining files in the containing directory.
 type WalkFunc func(path string, info FileInfo, err error) error
 
-type WalkFilesystem struct {
+type walkFilesystem struct {
 	Filesystem
 }
 
-func NewWalkFilesystem(next Filesystem) *WalkFilesystem {
-	return &WalkFilesystem{next}
+func NewWalkFilesystem(next Filesystem) Filesystem {
+	return &walkFilesystem{next}
 }
 
 // walk recursively descends path, calling walkFn.
-func (f *WalkFilesystem) walk(path string, info FileInfo, walkFn WalkFunc) error {
+func (f *walkFilesystem) walk(path string, info FileInfo, walkFn WalkFunc) error {
 	err := walkFn(path, info, nil)
 	if err != nil {
 		if info.IsDir() && err == SkipDir {
@@ -80,7 +80,7 @@ func (f *WalkFilesystem) walk(path string, info FileInfo, walkFn WalkFunc) error
 // order, which makes the output deterministic but means that for very
 // large directories Walk can be inefficient.
 // Walk does not follow symbolic links.
-func (f *WalkFilesystem) Walk(root string, walkFn WalkFunc) error {
+func (f *walkFilesystem) Walk(root string, walkFn WalkFunc) error {
 	info, err := f.Lstat(root)
 	if err != nil {
 		return walkFn(root, nil, err)

lib/ignore/ignore.go

@@ -12,13 +12,13 @@ import (
 	"crypto/md5"
 	"fmt"
 	"io"
-	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"time"
 
 	"github.com/gobwas/glob"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/sync"
 )
@@ -70,13 +70,14 @@ func (r Result) IsCaseFolded() bool {
 // called on it) and if any of the files have Changed(). To forget all
 // files, call Reset().
 type ChangeDetector interface {
-	Remember(name string, modtime time.Time)
-	Seen(name string) bool
+	Remember(fs fs.Filesystem, name string, modtime time.Time)
+	Seen(fs fs.Filesystem, name string) bool
 	Changed() bool
 	Reset()
 }
 
 type Matcher struct {
+	fs             fs.Filesystem
 	lines          []string  // exact lines read from .stignore
 	patterns       []Pattern // patterns including those from included files
 	withCache      bool
@@ -105,8 +106,9 @@ func WithChangeDetector(cd ChangeDetector) Option {
 	}
 }
 
-func New(opts ...Option) *Matcher {
+func New(fs fs.Filesystem, opts ...Option) *Matcher {
 	m := &Matcher{
+		fs:   fs,
 		stop: make(chan struct{}),
 		mut:  sync.NewMutex(),
 	}
@@ -126,11 +128,11 @@ func (m *Matcher) Load(file string) error {
 	m.mut.Lock()
 	defer m.mut.Unlock()
 
-	if m.changeDetector.Seen(file) && !m.changeDetector.Changed() {
+	if m.changeDetector.Seen(m.fs, file) && !m.changeDetector.Changed() {
 		return nil
 	}
 
-	fd, err := os.Open(file)
+	fd, err := m.fs.Open(file)
 	if err != nil {
 		m.parseLocked(&bytes.Buffer{}, file)
 		return err
@@ -144,7 +146,7 @@ func (m *Matcher) Load(file string) error {
 	}
 
 	m.changeDetector.Reset()
-	m.changeDetector.Remember(file, info.ModTime())
+	m.changeDetector.Remember(m.fs, file, info.ModTime())
 
 	return m.parseLocked(fd, file)
 }
@@ -156,7 +158,7 @@ func (m *Matcher) Parse(r io.Reader, file string) error {
 }
 
 func (m *Matcher) parseLocked(r io.Reader, file string) error {
-	lines, patterns, err := parseIgnoreFile(r, file, m.changeDetector)
+	lines, patterns, err := parseIgnoreFile(m.fs, r, file, m.changeDetector)
 	// Error is saved and returned at the end. We process the patterns
 	// (possibly blank) anyway.
 
@@ -298,12 +300,23 @@ func hashPatterns(patterns []Pattern) string {
 	return fmt.Sprintf("%x", h.Sum(nil))
 }
 
-func loadIgnoreFile(file string, cd ChangeDetector) ([]string, []Pattern, error) {
-	if cd.Seen(file) {
+func loadIgnoreFile(filesystem fs.Filesystem, file string, cd ChangeDetector) ([]string, []Pattern, error) {
+	if cd.Seen(filesystem, file) {
 		return nil, nil, fmt.Errorf("multiple include of ignore file %q", file)
 	}
 
-	fd, err := os.Open(file)
+	// Allow escaping the folders filesystem.
+	// TODO: Deprecate, somehow?
+	if filesystem.Type() == fs.FilesystemTypeBasic {
+		uri := filesystem.URI()
+		joined := filepath.Join(uri, file)
+		if !strings.HasPrefix(joined, uri) {
+			filesystem = fs.NewFilesystem(filesystem.Type(), filepath.Dir(joined))
+			file = filepath.Base(joined)
+		}
+	}
+
+	fd, err := filesystem.Open(file)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -314,12 +327,12 @@ func loadIgnoreFile(file string, cd ChangeDetector) ([]string, []Pattern, error)
 		return nil, nil, err
 	}
 
-	cd.Remember(file, info.ModTime())
+	cd.Remember(filesystem, file, info.ModTime())
 
-	return parseIgnoreFile(fd, file, cd)
+	return parseIgnoreFile(filesystem, fd, file, cd)
 }
 
-func parseIgnoreFile(fd io.Reader, currentFile string, cd ChangeDetector) ([]string, []Pattern, error) {
+func parseIgnoreFile(fs fs.Filesystem, fd io.Reader, currentFile string, cd ChangeDetector) ([]string, []Pattern, error) {
 	var lines []string
 	var patterns []Pattern
 
@@ -384,9 +397,9 @@ func parseIgnoreFile(fd io.Reader, currentFile string, cd ChangeDetector) ([]str
 			}
 			patterns = append(patterns, pattern)
 		} else if strings.HasPrefix(line, "#include ") {
-			includeRel := line[len("#include "):]
+			includeRel := strings.TrimSpace(line[len("#include "):])
 			includeFile := filepath.Join(filepath.Dir(currentFile), includeRel)
-			_, includePatterns, err := loadIgnoreFile(includeFile, cd)
+			_, includePatterns, err := loadIgnoreFile(fs, includeFile, cd)
 			if err != nil {
 				return fmt.Errorf("include of %q: %v", includeRel, err)
 			}
@@ -450,7 +463,7 @@ func parseIgnoreFile(fd io.Reader, currentFile string, cd ChangeDetector) ([]str
 // path must be clean (i.e., in canonical shortest form).
 func IsInternal(file string) bool {
 	internals := []string{".stfolder", ".stignore", ".stversions"}
-	pathSep := string(os.PathSeparator)
+	pathSep := string(fs.PathSeparator)
 	for _, internal := range internals {
 		if file == internal {
 			return true
@@ -463,8 +476,8 @@ func IsInternal(file string) bool {
 }
 
 // WriteIgnores is a convenience function to avoid code duplication
-func WriteIgnores(path string, content []string) error {
-	fd, err := osutil.CreateAtomic(path)
+func WriteIgnores(filesystem fs.Filesystem, path string, content []string) error {
+	fd, err := osutil.CreateAtomicFilesystem(filesystem, path)
 	if err != nil {
 		return err
 	}
@@ -476,38 +489,43 @@ func WriteIgnores(path string, content []string) error {
 	if err := fd.Close(); err != nil {
 		return err
 	}
-	osutil.HideFile(path)
+	filesystem.Hide(path)
 
 	return nil
 }
 
+type modtimeCheckerKey struct {
+	fs   fs.Filesystem
+	name string
+}
+
 // modtimeChecker is the default implementation of ChangeDetector
 type modtimeChecker struct {
-	modtimes map[string]time.Time
+	modtimes map[modtimeCheckerKey]time.Time
 }
 
 func newModtimeChecker() *modtimeChecker {
 	return &modtimeChecker{
-		modtimes: map[string]time.Time{},
+		modtimes: map[modtimeCheckerKey]time.Time{},
 	}
 }
 
-func (c *modtimeChecker) Remember(name string, modtime time.Time) {
-	c.modtimes[name] = modtime
+func (c *modtimeChecker) Remember(fs fs.Filesystem, name string, modtime time.Time) {
+	c.modtimes[modtimeCheckerKey{fs, name}] = modtime
 }
 
-func (c *modtimeChecker) Seen(name string) bool {
-	_, ok := c.modtimes[name]
+func (c *modtimeChecker) Seen(fs fs.Filesystem, name string) bool {
+	_, ok := c.modtimes[modtimeCheckerKey{fs, name}]
 	return ok
 }
 
 func (c *modtimeChecker) Reset() {
-	c.modtimes = map[string]time.Time{}
+	c.modtimes = map[modtimeCheckerKey]time.Time{}
 }
 
 func (c *modtimeChecker) Changed() bool {
-	for name, modtime := range c.modtimes {
-		info, err := os.Stat(name)
+	for key, modtime := range c.modtimes {
+		info, err := key.fs.Stat(key.name)
 		if err != nil {
 			return true
 		}

lib/ignore/ignore_test.go

@@ -15,11 +15,14 @@ import (
 	"runtime"
 	"testing"
 	"time"
+
+	"github.com/syncthing/syncthing/lib/fs"
+	"github.com/syncthing/syncthing/lib/osutil"
 )
 
 func TestIgnore(t *testing.T) {
-	pats := New(WithCache(true))
-	err := pats.Load("testdata/.stignore")
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"), WithCache(true))
+	err := pats.Load(".stignore")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -68,7 +71,7 @@ func TestExcludes(t *testing.T) {
 	i*2
 	!ign2
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -113,7 +116,7 @@ func TestFlagOrder(t *testing.T) {
 	(?i)(?d)(?d)!ign9
 	(?d)(?d)!ign10
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -148,7 +151,7 @@ func TestDeletables(t *testing.T) {
 	ign7
 	(?i)ign8
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -187,7 +190,7 @@ func TestBadPatterns(t *testing.T) {
 	}
 
 	for _, pat := range badPatterns {
-		err := New(WithCache(true)).Parse(bytes.NewBufferString(pat), ".stignore")
+		err := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true)).Parse(bytes.NewBufferString(pat), ".stignore")
 		if err == nil {
 			t.Errorf("No error for pattern %q", pat)
 		}
@@ -195,7 +198,7 @@ func TestBadPatterns(t *testing.T) {
 }
 
 func TestCaseSensitivity(t *testing.T) {
-	ign := New(WithCache(true))
+	ign := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := ign.Parse(bytes.NewBufferString("test"), ".stignore")
 	if err != nil {
 		t.Error(err)
@@ -225,29 +228,36 @@ func TestCaseSensitivity(t *testing.T) {
 }
 
 func TestCaching(t *testing.T) {
-	fd1, err := ioutil.TempFile("", "")
+	dir, err := ioutil.TempDir("", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	fd2, err := ioutil.TempFile("", "")
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
+
+	fd1, err := osutil.TempFile(fs, "", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fd2, err := osutil.TempFile(fs, "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	defer fd1.Close()
 	defer fd2.Close()
-	defer os.Remove(fd1.Name())
-	defer os.Remove(fd2.Name())
+	defer fs.Remove(fd1.Name())
+	defer fs.Remove(fd2.Name())
 
-	_, err = fd1.WriteString("/x/\n#include " + filepath.Base(fd2.Name()) + "\n")
+	_, err = fd1.Write([]byte("/x/\n#include " + filepath.Base(fd2.Name()) + "\n"))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	fd2.WriteString("/y/\n")
+	fd2.Write([]byte("/y/\n"))
 
-	pats := New(WithCache(true))
+	pats := New(fs, WithCache(true))
 	err = pats.Load(fd1.Name())
 	if err != nil {
 		t.Fatal(err)
@@ -280,10 +290,10 @@ func TestCaching(t *testing.T) {
 	// Modify the include file, expect empty cache. Ensure the timestamp on
 	// the file changes.
 
-	fd2.WriteString("/z/\n")
+	fd2.Write([]byte("/z/\n"))
 	fd2.Sync()
 	fakeTime := time.Now().Add(5 * time.Second)
-	os.Chtimes(fd2.Name(), fakeTime, fakeTime)
+	fs.Chtimes(fd2.Name(), fakeTime, fakeTime)
 
 	err = pats.Load(fd1.Name())
 	if err != nil {
@@ -312,10 +322,10 @@ func TestCaching(t *testing.T) {
 
 	// Modify the root file, expect cache to be invalidated
 
-	fd1.WriteString("/a/\n")
+	fd1.Write([]byte("/a/\n"))
 	fd1.Sync()
 	fakeTime = time.Now().Add(5 * time.Second)
-	os.Chtimes(fd1.Name(), fakeTime, fakeTime)
+	fs.Chtimes(fd1.Name(), fakeTime, fakeTime)
 
 	err = pats.Load(fd1.Name())
 	if err != nil {
@@ -354,7 +364,7 @@ func TestCommentsAndBlankLines(t *testing.T) {
 
 
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Error(err)
@@ -382,7 +392,7 @@ flamingo
 *.crow
 *.crow
 	`
-	pats := New()
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		b.Error(err)
@@ -411,20 +421,27 @@ flamingo
 *.crow
 	`
 	// Caches per file, hence write the patterns to a file.
-	fd, err := ioutil.TempFile("", "")
+	dir, err := ioutil.TempDir("", "")
 	if err != nil {
 		b.Fatal(err)
 	}
 
-	_, err = fd.WriteString(stignore)
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
+
+	fd, err := osutil.TempFile(fs, "", "")
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	_, err = fd.Write([]byte(stignore))
 	defer fd.Close()
-	defer os.Remove(fd.Name())
+	defer fs.Remove(fd.Name())
 	if err != nil {
 		b.Fatal(err)
 	}
 
 	// Load the patterns
-	pats := New(WithCache(true))
+	pats := New(fs, WithCache(true))
 	err = pats.Load(fd.Name())
 	if err != nil {
 		b.Fatal(err)
@@ -445,22 +462,29 @@ flamingo
 }
 
 func TestCacheReload(t *testing.T) {
-	fd, err := ioutil.TempFile("", "")
+	dir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
+
+	fd, err := osutil.TempFile(fs, "", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	defer fd.Close()
-	defer os.Remove(fd.Name())
+	defer fs.Remove(fd.Name())
 
 	// Ignore file matches f1 and f2
 
-	_, err = fd.WriteString("f1\nf2\n")
+	_, err = fd.Write([]byte("f1\nf2\n"))
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	pats := New(WithCache(true))
+	pats := New(fs, WithCache(true))
 	err = pats.Load(fd.Name())
 	if err != nil {
 		t.Fatal(err)
@@ -488,13 +512,13 @@ func TestCacheReload(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, err = fd.WriteString("f1\nf3\n")
+	_, err = fd.Write([]byte("f1\nf3\n"))
 	if err != nil {
 		t.Fatal(err)
 	}
 	fd.Sync()
 	fakeTime := time.Now().Add(5 * time.Second)
-	os.Chtimes(fd.Name(), fakeTime, fakeTime)
+	fs.Chtimes(fd.Name(), fakeTime, fakeTime)
 
 	err = pats.Load(fd.Name())
 	if err != nil {
@@ -515,7 +539,7 @@ func TestCacheReload(t *testing.T) {
 }
 
 func TestHash(t *testing.T) {
-	p1 := New(WithCache(true))
+	p1 := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := p1.Load("testdata/.stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -531,7 +555,7 @@ func TestHash(t *testing.T) {
 	/ffile
 	lost+found
 	`
-	p2 := New(WithCache(true))
+	p2 := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err = p2.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -546,7 +570,7 @@ func TestHash(t *testing.T) {
 	/ffile
 	lost+found
 	`
-	p3 := New(WithCache(true))
+	p3 := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err = p3.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -570,7 +594,7 @@ func TestHash(t *testing.T) {
 }
 
 func TestHashOfEmpty(t *testing.T) {
-	p1 := New(WithCache(true))
+	p1 := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := p1.Load("testdata/.stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -608,7 +632,7 @@ func TestWindowsPatterns(t *testing.T) {
 	a/b
 	c\d
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -633,7 +657,7 @@ func TestAutomaticCaseInsensitivity(t *testing.T) {
 	A/B
 	c/d
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -652,7 +676,7 @@ func TestCommas(t *testing.T) {
 	foo,bar.txt
 	{baz,quux}.txt
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -683,7 +707,7 @@ func TestIssue3164(t *testing.T) {
 	(?d)(?i)/foo
 	(?d)(?i)**/bar
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -719,7 +743,7 @@ func TestIssue3174(t *testing.T) {
 	stignore := `
 	*ä*
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -734,7 +758,7 @@ func TestIssue3639(t *testing.T) {
 	stignore := `
 	foo/
 	`
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -767,7 +791,7 @@ func TestIssue3674(t *testing.T) {
 		{"as/dc", true},
 	}
 
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -799,7 +823,7 @@ func TestGobwasGlobIssue18(t *testing.T) {
 		{"bbaa", false},
 	}
 
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -859,7 +883,7 @@ func TestRoot(t *testing.T) {
 		{"b", true},
 	}
 
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -876,12 +900,12 @@ func TestRoot(t *testing.T) {
 func TestLines(t *testing.T) {
 	stignore := `
 	#include testdata/excludes
-	
+
 	!/a
 	/*
 	`
 
-	pats := New(WithCache(true))
+	pats := New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."), WithCache(true))
 	err := pats.Parse(bytes.NewBufferString(stignore), ".stignore")
 	if err != nil {
 		t.Fatal(err)

lib/model/model.go

@@ -14,7 +14,6 @@ import (
 	"fmt"
 	"io"
 	"net"
-	"os"
 	"path/filepath"
 	"reflect"
 	"runtime"
@@ -81,6 +80,7 @@ type Model struct {
 	clientVersion string
 
 	folderCfgs         map[string]config.FolderConfiguration                  // folder -> cfg
+	folderFs           map[string]fs.Filesystem                               // folder -> fs
 	folderFiles        map[string]*db.FileSet                                 // folder -> files
 	folderDevices      folderDeviceSet                                        // folder -> deviceIDs
 	deviceFolders      map[protocol.DeviceID][]string                         // deviceID -> folders
@@ -99,21 +99,18 @@ type Model struct {
 	pmut                sync.RWMutex                   // protects the above
 }
 
-type folderFactory func(*Model, config.FolderConfiguration, versioner.Versioner, *fs.MtimeFS) service
+type folderFactory func(*Model, config.FolderConfiguration, versioner.Versioner, fs.Filesystem) service
 
 var (
 	folderFactories = make(map[config.FolderType]folderFactory, 0)
 )
 
 var (
-	errFolderPathEmpty     = errors.New("folder path empty")
 	errFolderPathMissing   = errors.New("folder path missing")
 	errFolderMarkerMissing = errors.New("folder marker missing")
-	errInvalidFilename     = errors.New("filename is invalid")
 	errDeviceUnknown       = errors.New("unknown device")
 	errDevicePaused        = errors.New("device is paused")
 	errDeviceIgnored       = errors.New("device is ignored")
-	errNotRelative         = errors.New("not a relative path")
 	errFolderPaused        = errors.New("folder is paused")
 	errFolderMissing       = errors.New("no such folder")
 	errNetworkNotAllowed   = errors.New("network not allowed")
@@ -140,6 +137,7 @@ func NewModel(cfg *config.Wrapper, id protocol.DeviceID, clientName, clientVersi
 		clientName:          clientName,
 		clientVersion:       clientVersion,
 		folderCfgs:          make(map[string]config.FolderConfiguration),
+		folderFs:            make(map[string]fs.Filesystem),
 		folderFiles:         make(map[string]*db.FileSet),
 		folderDevices:       make(folderDeviceSet),
 		deviceFolders:       make(map[protocol.DeviceID][]string),
@@ -245,7 +243,7 @@ func (m *Model) startFolderLocked(folder string) config.FolderType {
 			l.Fatalf("Requested versioning type %q that does not exist", cfg.Versioning.Type)
 		}
 
-		ver = versionerFactory(folder, cfg.Path(), cfg.Versioning.Params)
+		ver = versionerFactory(folder, cfg.Filesystem(), cfg.Versioning.Params)
 		if service, ok := ver.(suture.Service); ok {
 			// The versioner implements the suture.Service interface, so
 			// expects to be run in the background in addition to being called
@@ -271,7 +269,12 @@ func (m *Model) warnAboutOverwritingProtectedFiles(folder string) {
 		return
 	}
 
-	folderLocation := m.folderCfgs[folder].Path()
+	// This is a bit of a hack.
+	ffs := m.folderCfgs[folder].Filesystem()
+	if ffs.Type() != fs.FilesystemTypeBasic {
+		return
+	}
+	folderLocation := ffs.URI()
 	ignores := m.folderIgnores[folder]
 
 	var filesAtRisk []string
@@ -300,6 +303,10 @@ func (m *Model) AddFolder(cfg config.FolderConfiguration) {
 		panic("cannot add empty folder id")
 	}
 
+	if len(cfg.Path) == 0 {
+		panic("cannot add empty folder path")
+	}
+
 	m.fmut.Lock()
 	m.addFolderLocked(cfg)
 	m.fmut.Unlock()
@@ -307,15 +314,16 @@ func (m *Model) AddFolder(cfg config.FolderConfiguration) {
 
 func (m *Model) addFolderLocked(cfg config.FolderConfiguration) {
 	m.folderCfgs[cfg.ID] = cfg
-	m.folderFiles[cfg.ID] = db.NewFileSet(cfg.ID, m.db)
+	folderFs := cfg.Filesystem()
+	m.folderFiles[cfg.ID] = db.NewFileSet(cfg.ID, folderFs, m.db)
 
 	for _, device := range cfg.Devices {
 		m.folderDevices.set(device.DeviceID, cfg.ID)
 		m.deviceFolders[device.DeviceID] = append(m.deviceFolders[device.DeviceID], cfg.ID)
 	}
 
-	ignores := ignore.New(ignore.WithCache(m.cacheIgnoredFiles))
-	if err := ignores.Load(filepath.Join(cfg.Path(), ".stignore")); err != nil && !os.IsNotExist(err) {
+	ignores := ignore.New(folderFs, ignore.WithCache(m.cacheIgnoredFiles))
+	if err := ignores.Load(".stignore"); err != nil && !fs.IsNotExist(err) {
 		l.Warnln("Loading ignores:", err)
 	}
 	m.folderIgnores[cfg.ID] = ignores
@@ -327,8 +335,8 @@ func (m *Model) RemoveFolder(folder string) {
 
 	// Delete syncthing specific files
 	folderCfg := m.folderCfgs[folder]
-	folderPath := folderCfg.Path()
-	os.Remove(filepath.Join(folderPath, ".stfolder"))
+	fs := folderCfg.Filesystem()
+	fs.Remove(".stfolder")
 
 	m.tearDownFolderLocked(folder)
 	// Remove it from the database
@@ -1139,16 +1147,10 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
 	}
 	m.fmut.RLock()
 	folderCfg := m.folderCfgs[folder]
-	folderPath := folderCfg.Path()
 	folderIgnores := m.folderIgnores[folder]
 	m.fmut.RUnlock()
 
-	fn, err := rootedJoinedPath(folderPath, name)
-	if err != nil {
-		// Request tries to escape!
-		l.Debugf("%v Invalid REQ(in) tries to escape: %s: %q / %q o=%d s=%d", m, deviceID, folder, name, offset, len(buf))
-		return protocol.ErrInvalid
-	}
+	folderFs := folderCfg.Filesystem()
 
 	// Having passed the rootedJoinedPath check above, we know "name" is
 	// acceptable relative to "folderPath" and in canonical form, so we can
@@ -1164,7 +1166,7 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
 		return protocol.ErrNoSuchFile
 	}
 
-	if err := osutil.TraversesSymlink(folderPath, filepath.Dir(name)); err != nil {
+	if err := osutil.TraversesSymlink(folderFs, filepath.Dir(name)); err != nil {
 		l.Debugf("%v REQ(in) traversal check: %s - %s: %q / %q o=%d s=%d", m, err, deviceID, folder, name, offset, len(buf))
 		return protocol.ErrNoSuchFile
 	}
@@ -1172,29 +1174,29 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
 	// Only check temp files if the flag is set, and if we are set to advertise
 	// the temp indexes.
 	if fromTemporary && !folderCfg.DisableTempIndexes {
-		tempFn := filepath.Join(folderPath, ignore.TempName(name))
+		tempFn := ignore.TempName(name)
 
-		if info, err := osutil.Lstat(tempFn); err != nil || !info.Mode().IsRegular() {
+		if info, err := folderFs.Lstat(tempFn); err != nil || !info.IsRegular() {
 			// Reject reads for anything that doesn't exist or is something
 			// other than a regular file.
 			return protocol.ErrNoSuchFile
 		}
 
-		if err := readOffsetIntoBuf(tempFn, offset, buf); err == nil {
+		if err := readOffsetIntoBuf(folderFs, tempFn, offset, buf); err == nil {
 			return nil
 		}
 		// Fall through to reading from a non-temp file, just incase the temp
 		// file has finished downloading.
 	}
 
-	if info, err := osutil.Lstat(fn); err != nil || !info.Mode().IsRegular() {
+	if info, err := folderFs.Lstat(name); err != nil || !info.IsRegular() {
 		// Reject reads for anything that doesn't exist or is something
 		// other than a regular file.
 		return protocol.ErrNoSuchFile
 	}
 
-	err = readOffsetIntoBuf(fn, offset, buf)
-	if os.IsNotExist(err) {
+	err := readOffsetIntoBuf(folderFs, name, offset, buf)
+	if fs.IsNotExist(err) {
 		return protocol.ErrNoSuchFile
 	} else if err != nil {
 		return protocol.ErrGeneric
@@ -1245,30 +1247,31 @@ func (m *Model) ConnectedTo(deviceID protocol.DeviceID) bool {
 
 func (m *Model) GetIgnores(folder string) ([]string, []string, error) {
 	m.fmut.RLock()
+	defer m.fmut.RUnlock()
+
 	cfg, ok := m.folderCfgs[folder]
-	m.fmut.RUnlock()
-	if ok {
-		if !cfg.HasMarker() {
-			return nil, nil, fmt.Errorf("Folder %s stopped", folder)
+	if !ok {
+		cfg, ok = m.cfg.Folders()[folder]
+		if !ok {
+			return nil, nil, fmt.Errorf("Folder %s does not exist", folder)
 		}
+	}
 
-		m.fmut.RLock()
-		ignores := m.folderIgnores[folder]
-		m.fmut.RUnlock()
+	if err := m.checkFolderPath(cfg); err != nil {
+		return nil, nil, err
+	}
 
+	ignores, ok := m.folderIgnores[folder]
+	if ok {
 		return ignores.Lines(), ignores.Patterns(), nil
 	}
 
-	if cfg, ok := m.cfg.Folders()[folder]; ok {
-		matcher := ignore.New()
-		path := filepath.Join(cfg.Path(), ".stignore")
-		if err := matcher.Load(path); err != nil {
-			return nil, nil, err
-		}
-		return matcher.Lines(), matcher.Patterns(), nil
+	ignores = ignore.New(fs.NewFilesystem(cfg.FilesystemType, cfg.Path))
+	if err := ignores.Load(".stignore"); err != nil && !fs.IsNotExist(err) {
+		return nil, nil, err
 	}
 
-	return nil, nil, fmt.Errorf("Folder %s does not exist", folder)
+	return ignores.Lines(), ignores.Patterns(), nil
 }
 
 func (m *Model) SetIgnores(folder string, content []string) error {
@@ -1277,7 +1280,7 @@ func (m *Model) SetIgnores(folder string, content []string) error {
 		return fmt.Errorf("Folder %s does not exist", folder)
 	}
 
-	if err := ignore.WriteIgnores(filepath.Join(cfg.Path(), ".stignore"), content); err != nil {
+	if err := ignore.WriteIgnores(cfg.Filesystem(), ".stignore", content); err != nil {
 		l.Warnln("Saving .stignore:", err)
 		return err
 	}
@@ -1611,8 +1614,6 @@ func (m *Model) updateLocals(folder string, fs []protocol.FileInfo) {
 }
 
 func (m *Model) diskChangeDetected(folderCfg config.FolderConfiguration, files []protocol.FileInfo, typeOfEvent events.EventType) {
-	path := strings.Replace(folderCfg.Path(), `\\?\`, "", 1)
-
 	for _, file := range files {
 		objType := "file"
 		action := "modified"
@@ -1635,10 +1636,6 @@ func (m *Model) diskChangeDetected(folderCfg config.FolderConfiguration, files [
 			action = "deleted"
 		}
 
-		// The full file path, adjusted to the local path separator character.  Also
-		// for windows paths, strip unwanted chars from the front.
-		path := filepath.Join(path, filepath.FromSlash(file.Name))
-
 		// Two different events can be fired here based on what EventType is passed into function
 		events.Default.Log(typeOfEvent, map[string]string{
 			"folder":     folderCfg.ID,
@@ -1646,7 +1643,7 @@ func (m *Model) diskChangeDetected(folderCfg config.FolderConfiguration, files [
 			"label":      folderCfg.Label,
 			"action":     action,
 			"type":       objType,
-			"path":       path,
+			"path":       filepath.FromSlash(file.Name),
 			"modifiedBy": file.ModifiedBy.String(),
 		})
 	}
@@ -1739,20 +1736,17 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 		// not relevant, we just want the dotdot escape detection here. For
 		// historical reasons we may get paths that end in a slash. We
 		// remove that first to allow the rootedJoinedPath to pass.
-		sub = strings.TrimRight(sub, string(os.PathSeparator))
-		if _, err := rootedJoinedPath("root", sub); err != nil {
-			return errors.New("invalid subpath")
-		}
+		sub = strings.TrimRight(sub, string(fs.PathSeparator))
 		subDirs[i] = sub
 	}
 
 	m.fmut.Lock()
-	fs := m.folderFiles[folder]
+	fset := m.folderFiles[folder]
 	folderCfg := m.folderCfgs[folder]
 	ignores := m.folderIgnores[folder]
 	runner, ok := m.folderRunners[folder]
 	m.fmut.Unlock()
-	mtimefs := fs.MtimeFS()
+	mtimefs := fset.MtimeFS()
 
 	// Check if the ignore patterns changed as part of scanning this folder.
 	// If they did we should schedule a pull of the folder so that we
@@ -1779,7 +1773,7 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 		return err
 	}
 
-	if err := ignores.Load(filepath.Join(folderCfg.Path(), ".stignore")); err != nil && !os.IsNotExist(err) {
+	if err := ignores.Load(".stignore"); err != nil && !fs.IsNotExist(err) {
 		err = fmt.Errorf("loading ignores: %v", err)
 		runner.setError(err)
 		l.Infof("Stopping folder %s due to error: %s", folderCfg.Description(), err)
@@ -1790,7 +1784,7 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 	// directory, and don't scan subdirectories of things we've already
 	// scanned.
 	subDirs = unifySubs(subDirs, func(f string) bool {
-		_, ok := fs.Get(protocol.LocalDeviceID, f)
+		_, ok := fset.Get(protocol.LocalDeviceID, f)
 		return ok
 	})
 
@@ -1798,7 +1792,6 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 
 	fchan, err := scanner.Walk(ctx, scanner.Config{
 		Folder:                folderCfg.ID,
-		Dir:                   folderCfg.Path(),
 		Subs:                  subDirs,
 		Matcher:               ignores,
 		BlockSize:             protocol.BlockSize,
@@ -1861,7 +1854,7 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 	for _, sub := range subDirs {
 		var iterError error
 
-		fs.WithPrefixedHaveTruncated(protocol.LocalDeviceID, sub, func(fi db.FileIntf) bool {
+		fset.WithPrefixedHaveTruncated(protocol.LocalDeviceID, sub, func(fi db.FileIntf) bool {
 			f := fi.(db.FileInfoTruncated)
 			if len(batch) == maxBatchSizeFiles || batchSizeBytes > maxBatchSizeBytes {
 				if err := m.CheckFolderHealth(folder); err != nil {
@@ -1896,9 +1889,9 @@ func (m *Model) internalScanFolderSubdirs(ctx context.Context, folder string, su
 				// The file is valid and not deleted. Lets check if it's
 				// still here.
 
-				if _, err := mtimefs.Lstat(filepath.Join(folderCfg.Path(), f.Name)); err != nil {
+				if _, err := mtimefs.Lstat(f.Name); err != nil {
 					// We don't specifically verify that the error is
-					// os.IsNotExist because there is a corner case when a
+					// fs.IsNotExist because there is a corner case when a
 					// directory is suddenly transformed into a file. When that
 					// happens, files that were in the directory (that is now a
 					// file) are deleted but will return a confusing error ("not a
@@ -2276,11 +2269,9 @@ func (m *Model) CheckFolderHealth(id string) error {
 
 // checkFolderPath returns nil if the folder path exists and has the marker file.
 func (m *Model) checkFolderPath(folder config.FolderConfiguration) error {
-	if folder.Path() == "" {
-		return errFolderPathEmpty
-	}
+	fs := folder.Filesystem()
 
-	if fi, err := os.Stat(folder.Path()); err != nil || !fi.IsDir() {
+	if fi, err := fs.Stat("."); err != nil || !fi.IsDir() {
 		return errFolderPathMissing
 	}
 
@@ -2294,30 +2285,31 @@ func (m *Model) checkFolderPath(folder config.FolderConfiguration) error {
 // checkFolderFreeSpace returns nil if the folder has the required amount of
 // free space, or if folder free space checking is disabled.
 func (m *Model) checkFolderFreeSpace(folder config.FolderConfiguration) error {
-	return m.checkFreeSpace(folder.MinDiskFree, folder.Path())
+	return m.checkFreeSpace(folder.MinDiskFree, folder.Filesystem())
 }
 
 // checkHomeDiskFree returns nil if the home disk has the required amount of
 // free space, or if home disk free space checking is disabled.
 func (m *Model) checkHomeDiskFree() error {
-	return m.checkFreeSpace(m.cfg.Options().MinHomeDiskFree, m.cfg.ConfigPath())
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, filepath.Dir(m.cfg.ConfigPath()))
+	return m.checkFreeSpace(m.cfg.Options().MinHomeDiskFree, fs)
 }
 
-func (m *Model) checkFreeSpace(req config.Size, path string) error {
+func (m *Model) checkFreeSpace(req config.Size, fs fs.Filesystem) error {
 	val := req.BaseValue()
 	if val <= 0 {
 		return nil
 	}
 
+	usage, err := fs.Usage(".")
 	if req.Percentage() {
-		free, err := osutil.DiskFreePercentage(path)
-		if err == nil && free < val {
-			return fmt.Errorf("insufficient space in %v: %f %% < %v", path, free, req)
+		freePct := (float64(usage.Free) / float64(usage.Total)) * 100
+		if err == nil && freePct < val {
+			return fmt.Errorf("insufficient space in %v %v: %f %% < %v", fs.Type(), fs.URI(), freePct, req)
 		}
 	} else {
-		free, err := osutil.DiskFreeBytes(path)
-		if err == nil && float64(free) < val {
-			return fmt.Errorf("insufficient space in %v: %v < %v", path, free, req)
+		if err == nil && float64(usage.Free) < val {
+			return fmt.Errorf("insufficient space in %v %v: %v < %v", fs.Type(), fs.URI(), usage.Free, req)
 		}
 	}
 
@@ -2534,8 +2526,8 @@ func stringSliceWithout(ss []string, s string) []string {
 	return ss
 }
 
-func readOffsetIntoBuf(file string, offset int64, buf []byte) error {
-	fd, err := os.Open(file)
+func readOffsetIntoBuf(fs fs.Filesystem, file string, offset int64, buf []byte) error {
+	fd, err := fs.Open(file)
 	if err != nil {
 		l.Debugln("readOffsetIntoBuf.Open", file, err)
 		return err
@@ -2586,7 +2578,7 @@ func simplifySortedPaths(subs []string) []string {
 next:
 	for _, sub := range subs {
 		for _, existing := range cleaned {
-			if sub == existing || strings.HasPrefix(sub, existing+string(os.PathSeparator)) {
+			if sub == existing || strings.HasPrefix(sub, existing+string(fs.PathSeparator)) {
 				continue next
 			}
 		}
@@ -2667,57 +2659,3 @@ func (s folderDeviceSet) sortedDevices(folder string) []protocol.DeviceID {
 	sort.Sort(protocol.DeviceIDs(devs))
 	return devs
 }
-
-// rootedJoinedPath takes a root and a supposedly relative path inside that
-// root and returns the joined path. An error is returned if the joined path
-// is not in fact inside the root.
-func rootedJoinedPath(root, rel string) (string, error) {
-	// The root must not be empty.
-	if root == "" {
-		return "", errInvalidFilename
-	}
-
-	pathSep := string(os.PathSeparator)
-
-	// The expected prefix for the resulting path is the root, with a path
-	// separator at the end.
-	expectedPrefix := filepath.FromSlash(root)
-	if !strings.HasSuffix(expectedPrefix, pathSep) {
-		expectedPrefix += pathSep
-	}
-
-	// The relative path should be clean from internal dotdots and similar
-	// funkyness.
-	rel = filepath.FromSlash(rel)
-	if filepath.Clean(rel) != rel {
-		return "", errInvalidFilename
-	}
-
-	// It is not acceptable to attempt to traverse upwards or refer to the
-	// root itself.
-	switch rel {
-	case ".", "..", pathSep:
-		return "", errNotRelative
-	}
-	if strings.HasPrefix(rel, ".."+pathSep) {
-		return "", errNotRelative
-	}
-
-	if strings.HasPrefix(rel, pathSep+pathSep) {
-		// The relative path may pretend to be an absolute path within the
-		// root, but the double path separator on Windows implies something
-		// else. It would get cleaned by the Join below, but it's out of
-		// spec anyway.
-		return "", errNotRelative
-	}
-
-	// The supposedly correct path is the one filepath.Join will return, as
-	// it does cleaning and so on. Check that one first to make sure no
-	// obvious escape attempts have been made.
-	joined := filepath.Join(root, rel)
-	if !strings.HasPrefix(joined, expectedPrefix) {
-		return "", errNotRelative
-	}
-
-	return joined, nil
-}

lib/model/model_test.go

@@ -25,8 +25,8 @@ import (
 	"github.com/d4l3k/messagediff"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/ignore"
-	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
 	srand "github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/scanner"
@@ -35,12 +35,14 @@ import (
 var device1, device2 protocol.DeviceID
 var defaultConfig *config.Wrapper
 var defaultFolderConfig config.FolderConfiguration
+var defaultFs fs.Filesystem
 
 func init() {
 	device1, _ = protocol.DeviceIDFromString("AIR6LPZ-7K4PTTV-UXQSMUU-CPQ5YWH-OEDFIIQ-JUG777G-2YQXXR5-YD6AWQR")
 	device2, _ = protocol.DeviceIDFromString("GYRZZQB-IRNPV4Z-T7TC52W-EQYJ3TT-FDQW6MW-DFLMU42-SSSU6EM-FBK2VAY")
+	defaultFs = fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata")
 
-	defaultFolderConfig = config.NewFolderConfiguration("default", "testdata")
+	defaultFolderConfig = config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "testdata")
 	defaultFolderConfig.Devices = []config.FolderDeviceConfiguration{{DeviceID: device1}}
 	_defaultConfig := config.Configuration{
 		Folders: []config.FolderConfiguration{defaultFolderConfig},
@@ -350,6 +352,24 @@ func (f *fakeConnection) addFile(name string, flags uint32, ftype protocol.FileI
 	f.fileData[name] = data
 }
 
+func (f *fakeConnection) deleteFile(name string) {
+	f.mut.Lock()
+	defer f.mut.Unlock()
+
+	for i, fi := range f.files {
+		if fi.Name == name {
+			fi.Deleted = true
+			fi.ModifiedS = time.Now().Unix()
+			fi.Version = fi.Version.Update(f.id.Short())
+			fi.Sequence = time.Now().UnixNano()
+			fi.Blocks = nil
+
+			f.files = append(append(f.files[:i], f.files[i+1:]...), fi)
+			return
+		}
+	}
+}
+
 func (f *fakeConnection) sendIndexUpdate() {
 	f.model.IndexUpdate(f.id, f.folder, f.files)
 }
@@ -495,14 +515,16 @@ func TestClusterConfig(t *testing.T) {
 	}
 	cfg.Folders = []config.FolderConfiguration{
 		{
-			ID: "folder1",
+			ID:   "folder1",
+			Path: "testdata",
 			Devices: []config.FolderDeviceConfiguration{
 				{DeviceID: device1},
 				{DeviceID: device2},
 			},
 		},
 		{
-			ID: "folder2",
+			ID:   "folder2",
+			Path: "testdata",
 			Devices: []config.FolderDeviceConfiguration{
 				{DeviceID: device1},
 				{DeviceID: device2},
@@ -604,13 +626,15 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 				},
@@ -653,14 +677,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 				},
@@ -708,14 +734,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
@@ -753,14 +781,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
@@ -798,14 +828,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 				},
@@ -854,14 +886,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2},
@@ -898,14 +932,16 @@ func TestIntroducer(t *testing.T) {
 		},
 		Folders: []config.FolderConfiguration{
 			{
-				ID: "folder1",
+				ID:   "folder1",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: device1},
 				},
 			},
 			{
-				ID: "folder2",
+				ID:   "folder2",
+				Path: "testdata",
 				Devices: []config.FolderDeviceConfiguration{
 					{DeviceID: device1},
 					{DeviceID: device2, IntroducedBy: protocol.LocalDeviceID},
@@ -1008,7 +1044,7 @@ func TestIgnores(t *testing.T) {
 	// because we will be changing the files on disk often enough that the
 	// mtimes will be unreliable to determine change status.
 	m.fmut.Lock()
-	m.folderIgnores["default"] = ignore.New(ignore.WithCache(true), ignore.WithChangeDetector(newAlwaysChanged()))
+	m.folderIgnores["default"] = ignore.New(defaultFs, ignore.WithCache(true), ignore.WithChangeDetector(newAlwaysChanged()))
 	m.fmut.Unlock()
 
 	// Make sure the initial scan has finished (ScanFolders is blocking)
@@ -1032,7 +1068,7 @@ func TestIgnores(t *testing.T) {
 	}
 
 	// Invalid path, marker should be missing, hence returns an error.
-	m.AddFolder(config.FolderConfiguration{ID: "fresh", RawPath: "XXX"})
+	m.AddFolder(config.FolderConfiguration{ID: "fresh", Path: "XXX"})
 	_, _, err = m.GetIgnores("fresh")
 	if err == nil {
 		t.Error("No error")
@@ -1047,18 +1083,23 @@ func TestIgnores(t *testing.T) {
 	// added to the model and thus there is no initial scan happening.
 
 	changeIgnores(t, m, expected)
+
+	// Make sure no .stignore file is considered valid
+	os.Rename("testdata/.stignore", "testdata/.stignore.bak")
+	changeIgnores(t, m, []string{})
+	os.Rename("testdata/.stignore.bak", "testdata/.stignore")
 }
 
 func TestROScanRecovery(t *testing.T) {
 	ldb := db.OpenMemory()
-	set := db.NewFileSet("default", ldb)
+	set := db.NewFileSet("default", defaultFs, ldb)
 	set.Update(protocol.LocalDeviceID, []protocol.FileInfo{
 		{Name: "dummyfile"},
 	})
 
 	fcfg := config.FolderConfiguration{
 		ID:              "default",
-		RawPath:         "testdata/rotestfolder",
+		Path:            "testdata/rotestfolder",
 		Type:            config.FolderTypeSendOnly,
 		RescanIntervalS: 1,
 	}
@@ -1071,7 +1112,7 @@ func TestROScanRecovery(t *testing.T) {
 		},
 	})
 
-	os.RemoveAll(fcfg.RawPath)
+	os.RemoveAll(fcfg.Path)
 
 	m := NewModel(cfg, protocol.LocalDeviceID, "syncthing", "dev", ldb, nil)
 	m.AddFolder(fcfg)
@@ -1102,14 +1143,14 @@ func TestROScanRecovery(t *testing.T) {
 		return
 	}
 
-	os.Mkdir(fcfg.RawPath, 0700)
+	os.Mkdir(fcfg.Path, 0700)
 
 	if err := waitFor("folder marker missing"); err != nil {
 		t.Error(err)
 		return
 	}
 
-	fd, err := os.Create(filepath.Join(fcfg.RawPath, ".stfolder"))
+	fd, err := os.Create(filepath.Join(fcfg.Path, ".stfolder"))
 	if err != nil {
 		t.Error(err)
 		return
@@ -1121,14 +1162,14 @@ func TestROScanRecovery(t *testing.T) {
 		return
 	}
 
-	os.Remove(filepath.Join(fcfg.RawPath, ".stfolder"))
+	os.Remove(filepath.Join(fcfg.Path, ".stfolder"))
 
 	if err := waitFor("folder marker missing"); err != nil {
 		t.Error(err)
 		return
 	}
 
-	os.Remove(fcfg.RawPath)
+	os.Remove(fcfg.Path)
 
 	if err := waitFor("folder path missing"); err != nil {
 		t.Error(err)
@@ -1138,14 +1179,14 @@ func TestROScanRecovery(t *testing.T) {
 
 func TestRWScanRecovery(t *testing.T) {
 	ldb := db.OpenMemory()
-	set := db.NewFileSet("default", ldb)
+	set := db.NewFileSet("default", defaultFs, ldb)
 	set.Update(protocol.LocalDeviceID, []protocol.FileInfo{
 		{Name: "dummyfile"},
 	})
 
 	fcfg := config.FolderConfiguration{
 		ID:              "default",
-		RawPath:         "testdata/rwtestfolder",
+		Path:            "testdata/rwtestfolder",
 		Type:            config.FolderTypeSendReceive,
 		RescanIntervalS: 1,
 	}
@@ -1158,7 +1199,7 @@ func TestRWScanRecovery(t *testing.T) {
 		},
 	})
 
-	os.RemoveAll(fcfg.RawPath)
+	os.RemoveAll(fcfg.Path)
 
 	m := NewModel(cfg, protocol.LocalDeviceID, "syncthing", "dev", ldb, nil)
 	m.AddFolder(fcfg)
@@ -1189,14 +1230,14 @@ func TestRWScanRecovery(t *testing.T) {
 		return
 	}
 
-	os.Mkdir(fcfg.RawPath, 0700)
+	os.Mkdir(fcfg.Path, 0700)
 
 	if err := waitFor("folder marker missing"); err != nil {
 		t.Error(err)
 		return
 	}
 
-	fd, err := os.Create(filepath.Join(fcfg.RawPath, ".stfolder"))
+	fd, err := os.Create(filepath.Join(fcfg.Path, ".stfolder"))
 	if err != nil {
 		t.Error(err)
 		return
@@ -1208,14 +1249,14 @@ func TestRWScanRecovery(t *testing.T) {
 		return
 	}
 
-	os.Remove(filepath.Join(fcfg.RawPath, ".stfolder"))
+	os.Remove(filepath.Join(fcfg.Path, ".stfolder"))
 
 	if err := waitFor("folder marker missing"); err != nil {
 		t.Error(err)
 		return
 	}
 
-	os.Remove(fcfg.RawPath)
+	os.Remove(fcfg.Path)
 
 	if err := waitFor("folder path missing"); err != nil {
 		t.Error(err)
@@ -1843,14 +1884,14 @@ func TestIssue3164(t *testing.T) {
 	f := protocol.FileInfo{
 		Name: "issue3164",
 	}
-	m := ignore.New()
+	m := ignore.New(defaultFs)
 	if err := m.Parse(bytes.NewBufferString("(?d)oktodelete"), ""); err != nil {
 		t.Fatal(err)
 	}
 
 	fl := sendReceiveFolder{
 		dbUpdates: make(chan dbUpdateJob, 1),
-		dir:       "testdata",
+		fs:        fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
 	}
 
 	fl.deleteDir(f, m)
@@ -1937,7 +1978,7 @@ func TestIssue2782(t *testing.T) {
 	if err := os.RemoveAll(testDir); err != nil {
 		t.Skip(err)
 	}
-	if err := osutil.MkdirAll(testDir+"/syncdir", 0755); err != nil {
+	if err := os.MkdirAll(testDir+"/syncdir", 0755); err != nil {
 		t.Skip(err)
 	}
 	if err := ioutil.WriteFile(testDir+"/syncdir/file", []byte("hello, world\n"), 0644); err != nil {
@@ -1950,7 +1991,7 @@ func TestIssue2782(t *testing.T) {
 
 	db := db.OpenMemory()
 	m := NewModel(defaultConfig, protocol.LocalDeviceID, "syncthing", "dev", db, nil)
-	m.AddFolder(config.NewFolderConfiguration("default", "~/"+testName+"/synclink/"))
+	m.AddFolder(config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "~/"+testName+"/synclink/"))
 	m.StartFolder("default")
 	m.ServeBackground()
 	defer m.Stop()
@@ -1967,7 +2008,7 @@ func TestIssue2782(t *testing.T) {
 func TestIndexesForUnknownDevicesDropped(t *testing.T) {
 	dbi := db.OpenMemory()
 
-	files := db.NewFileSet("default", dbi)
+	files := db.NewFileSet("default", defaultFs, dbi)
 	files.Replace(device1, genFiles(1))
 	files.Replace(device2, genFiles(1))
 
@@ -1980,7 +2021,7 @@ func TestIndexesForUnknownDevicesDropped(t *testing.T) {
 	m.StartFolder("default")
 
 	// Remote sequence is cached, hence need to recreated.
-	files = db.NewFileSet("default", dbi)
+	files = db.NewFileSet("default", defaultFs, dbi)
 
 	if len(files.ListDevices()) != 1 {
 		t.Error("Expected one device")
@@ -1990,7 +2031,7 @@ func TestIndexesForUnknownDevicesDropped(t *testing.T) {
 func TestSharedWithClearedOnDisconnect(t *testing.T) {
 	dbi := db.OpenMemory()
 
-	fcfg := config.NewFolderConfiguration("default", "testdata")
+	fcfg := config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "testdata")
 	fcfg.Devices = []config.FolderDeviceConfiguration{
 		{DeviceID: device1},
 		{DeviceID: device2},
@@ -2229,7 +2270,7 @@ func TestNoRequestsFromPausedDevices(t *testing.T) {
 
 	dbi := db.OpenMemory()
 
-	fcfg := config.NewFolderConfiguration("default", "testdata")
+	fcfg := config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "testdata")
 	fcfg.Devices = []config.FolderDeviceConfiguration{
 		{DeviceID: device1},
 		{DeviceID: device2},
@@ -2317,151 +2358,6 @@ func TestNoRequestsFromPausedDevices(t *testing.T) {
 	}
 }
 
-func TestRootedJoinedPath(t *testing.T) {
-	type testcase struct {
-		root   string
-		rel    string
-		joined string
-		ok     bool
-	}
-	cases := []testcase{
-		// Valid cases
-		{"foo", "bar", "foo/bar", true},
-		{"foo", "/bar", "foo/bar", true},
-		{"foo/", "bar", "foo/bar", true},
-		{"foo/", "/bar", "foo/bar", true},
-		{"baz/foo", "bar", "baz/foo/bar", true},
-		{"baz/foo", "/bar", "baz/foo/bar", true},
-		{"baz/foo/", "bar", "baz/foo/bar", true},
-		{"baz/foo/", "/bar", "baz/foo/bar", true},
-		{"foo", "bar/baz", "foo/bar/baz", true},
-		{"foo", "/bar/baz", "foo/bar/baz", true},
-		{"foo/", "bar/baz", "foo/bar/baz", true},
-		{"foo/", "/bar/baz", "foo/bar/baz", true},
-		{"baz/foo", "bar/baz", "baz/foo/bar/baz", true},
-		{"baz/foo", "/bar/baz", "baz/foo/bar/baz", true},
-		{"baz/foo/", "bar/baz", "baz/foo/bar/baz", true},
-		{"baz/foo/", "/bar/baz", "baz/foo/bar/baz", true},
-
-		// Not escape attempts, but oddly formatted relative paths. Disallowed.
-		{"foo", "./bar", "", false},
-		{"baz/foo", "./bar", "", false},
-		{"foo", "./bar/baz", "", false},
-		{"baz/foo", "./bar/baz", "", false},
-		{"baz/foo", "bar/../baz", "", false},
-		{"baz/foo", "/bar/../baz", "", false},
-		{"baz/foo", "./bar/../baz", "", false},
-		{"baz/foo", "bar/../baz", "", false},
-		{"baz/foo", "/bar/../baz", "", false},
-		{"baz/foo", "./bar/../baz", "", false},
-
-		// Results in an allowed path, but does it by probing. Disallowed.
-		{"foo", "../foo", "", false},
-		{"foo", "../foo/bar", "", false},
-		{"baz/foo", "../foo/bar", "", false},
-		{"baz/foo", "../../baz/foo/bar", "", false},
-		{"baz/foo", "bar/../../foo/bar", "", false},
-		{"baz/foo", "bar/../../../baz/foo/bar", "", false},
-
-		// Escape attempts.
-		{"foo", "", "", false},
-		{"foo", "/", "", false},
-		{"foo", "..", "", false},
-		{"foo", "/..", "", false},
-		{"foo", "../", "", false},
-		{"foo", "../bar", "", false},
-		{"foo", "../foobar", "", false},
-		{"foo/", "../bar", "", false},
-		{"foo/", "../foobar", "", false},
-		{"baz/foo", "../bar", "", false},
-		{"baz/foo", "../foobar", "", false},
-		{"baz/foo/", "../bar", "", false},
-		{"baz/foo/", "../foobar", "", false},
-		{"baz/foo/", "bar/../../quux/baz", "", false},
-
-		// Empty root is a misconfiguration.
-		{"", "/foo", "", false},
-		{"", "foo", "", false},
-		{"", ".", "", false},
-		{"", "..", "", false},
-		{"", "/", "", false},
-		{"", "", "", false},
-
-		// Root=/ is valid, and things should be verified as usual.
-		{"/", "foo", "/foo", true},
-		{"/", "/foo", "/foo", true},
-		{"/", "../foo", "", false},
-		{"/", ".", "", false},
-		{"/", "..", "", false},
-		{"/", "/", "", false},
-		{"/", "", "", false},
-	}
-
-	if runtime.GOOS == "windows" {
-		extraCases := []testcase{
-			{`c:\`, `foo`, `c:\foo`, true},
-			{`\\?\c:\`, `foo`, `\\?\c:\foo`, true},
-			{`c:\`, `\foo`, `c:\foo`, true},
-			{`\\?\c:\`, `\foo`, `\\?\c:\foo`, true},
-
-			{`c:\`, `\\foo`, ``, false},
-			{`c:\`, ``, ``, false},
-			{`c:\`, `.`, ``, false},
-			{`c:\`, `\`, ``, false},
-			{`\\?\c:\`, `\\foo`, ``, false},
-			{`\\?\c:\`, ``, ``, false},
-			{`\\?\c:\`, `.`, ``, false},
-			{`\\?\c:\`, `\`, ``, false},
-
-			// makes no sense, but will be treated simply as a bad filename
-			{`c:\foo`, `d:\bar`, `c:\foo\d:\bar`, true},
-		}
-
-		for _, tc := range cases {
-			// Add case where root is backslashed, rel is forward slashed
-			extraCases = append(extraCases, testcase{
-				root:   filepath.FromSlash(tc.root),
-				rel:    tc.rel,
-				joined: tc.joined,
-				ok:     tc.ok,
-			})
-			// and the opposite
-			extraCases = append(extraCases, testcase{
-				root:   tc.root,
-				rel:    filepath.FromSlash(tc.rel),
-				joined: tc.joined,
-				ok:     tc.ok,
-			})
-			// and both backslashed
-			extraCases = append(extraCases, testcase{
-				root:   filepath.FromSlash(tc.root),
-				rel:    filepath.FromSlash(tc.rel),
-				joined: tc.joined,
-				ok:     tc.ok,
-			})
-		}
-
-		cases = append(cases, extraCases...)
-	}
-
-	for _, tc := range cases {
-		res, err := rootedJoinedPath(tc.root, tc.rel)
-		if tc.ok {
-			if err != nil {
-				t.Errorf("Unexpected error for rootedJoinedPath(%q, %q): %v", tc.root, tc.rel, err)
-				continue
-			}
-			exp := filepath.FromSlash(tc.joined)
-			if res != exp {
-				t.Errorf("Unexpected result for rootedJoinedPath(%q, %q): %q != expected %q", tc.root, tc.rel, res, exp)
-			}
-		} else if err == nil {
-			t.Errorf("Unexpected pass for rootedJoinedPath(%q, %q) => %q", tc.root, tc.rel, res)
-			continue
-		}
-	}
-}
-
 func addFakeConn(m *Model, dev protocol.DeviceID) *fakeConnection {
 	fc := &fakeConnection{id: dev, model: m}
 	m.AddConnection(fc, protocol.HelloResult{})
@@ -2491,27 +2387,32 @@ func (fakeAddr) String() string {
 	return "address"
 }
 
+type alwaysChangedKey struct {
+	fs   fs.Filesystem
+	name string
+}
+
 // alwaysChanges is an ignore.ChangeDetector that always returns true on Changed()
 type alwaysChanged struct {
-	seen map[string]struct{}
+	seen map[alwaysChangedKey]struct{}
 }
 
 func newAlwaysChanged() *alwaysChanged {
 	return &alwaysChanged{
-		seen: make(map[string]struct{}),
+		seen: make(map[alwaysChangedKey]struct{}),
 	}
 }
 
-func (c *alwaysChanged) Remember(name string, _ time.Time) {
-	c.seen[name] = struct{}{}
+func (c *alwaysChanged) Remember(fs fs.Filesystem, name string, _ time.Time) {
+	c.seen[alwaysChangedKey{fs, name}] = struct{}{}
 }
 
 func (c *alwaysChanged) Reset() {
-	c.seen = make(map[string]struct{})
+	c.seen = make(map[alwaysChangedKey]struct{})
 }
 
-func (c *alwaysChanged) Seen(name string) bool {
-	_, ok := c.seen[name]
+func (c *alwaysChanged) Seen(fs fs.Filesystem, name string) bool {
+	_, ok := c.seen[alwaysChangedKey{fs, name}]
 	return ok
 }
 

lib/model/requests_test.go

@@ -10,6 +10,7 @@ import (
 	"bytes"
 	"io/ioutil"
 	"os"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
@@ -17,6 +18,7 @@ import (
 
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 )
 
@@ -204,9 +206,89 @@ func TestRequestCreateTmpSymlink(t *testing.T) {
 	}
 }
 
+func TestRequestVersioningSymlinkAttack(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("no symlink support on Windows")
+	}
+
+	// Sets up a folder with trashcan versioning and tries to use a
+	// deleted symlink to escape
+
+	cfg := defaultConfig.RawCopy()
+	cfg.Folders[0] = config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "_tmpfolder")
+	cfg.Folders[0].PullerSleepS = 1
+	cfg.Folders[0].Devices = []config.FolderDeviceConfiguration{
+		{DeviceID: device1},
+		{DeviceID: device2},
+	}
+	cfg.Folders[0].Versioning = config.VersioningConfiguration{
+		Type: "trashcan",
+	}
+	w := config.Wrap("/tmp/cfg", cfg)
+
+	db := db.OpenMemory()
+	m := NewModel(w, device1, "syncthing", "dev", db, nil)
+	m.AddFolder(cfg.Folders[0])
+	m.ServeBackground()
+	m.StartFolder("default")
+	defer m.Stop()
+
+	defer os.RemoveAll("_tmpfolder")
+
+	fc := addFakeConn(m, device2)
+	fc.folder = "default"
+
+	// Create a temporary directory that we will use as target to see if
+	// we can escape to it
+	tmpdir, err := ioutil.TempDir("", "syncthing-test")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// We listen for incoming index updates and trigger when we see one for
+	// the expected test file.
+	idx := make(chan int)
+	fc.mut.Lock()
+	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
+		idx <- len(fs)
+	}
+	fc.mut.Unlock()
+
+	// Send an update for the test file, wait for it to sync and be reported back.
+	fc.addFile("foo", 0644, protocol.FileInfoTypeSymlink, []byte(tmpdir))
+	fc.sendIndexUpdate()
+
+	for updates := 0; updates < 1; updates += <-idx {
+	}
+
+	// Delete the symlink, hoping for it to get versioned
+	fc.deleteFile("foo")
+	fc.sendIndexUpdate()
+	for updates := 0; updates < 1; updates += <-idx {
+	}
+
+	// Recreate foo and a file in it with some data
+	fc.addFile("foo", 0755, protocol.FileInfoTypeDirectory, nil)
+	fc.addFile("foo/test", 0644, protocol.FileInfoTypeFile, []byte("testtesttest"))
+	fc.sendIndexUpdate()
+	for updates := 0; updates < 1; updates += <-idx {
+	}
+
+	// Remove the test file and see if it escaped
+	fc.deleteFile("foo/test")
+	fc.sendIndexUpdate()
+	for updates := 0; updates < 1; updates += <-idx {
+	}
+
+	path := filepath.Join(tmpdir, "test")
+	if _, err := os.Lstat(path); !os.IsNotExist(err) {
+		t.Fatal("File escaped to", path)
+	}
+}
+
 func setupModelWithConnection() (*Model, *fakeConnection) {
 	cfg := defaultConfig.RawCopy()
-	cfg.Folders[0] = config.NewFolderConfiguration("default", "_tmpfolder")
+	cfg.Folders[0] = config.NewFolderConfiguration("default", fs.FilesystemTypeBasic, "_tmpfolder")
 	cfg.Folders[0].PullerSleepS = 1
 	cfg.Folders[0].Devices = []config.FolderDeviceConfiguration{
 		{DeviceID: device1},

lib/model/rofolder.go

@@ -24,7 +24,7 @@ type sendOnlyFolder struct {
 	config.FolderConfiguration
 }
 
-func newSendOnlyFolder(model *Model, cfg config.FolderConfiguration, _ versioner.Versioner, _ *fs.MtimeFS) service {
+func newSendOnlyFolder(model *Model, cfg config.FolderConfiguration, _ versioner.Versioner, _ fs.Filesystem) service {
 	ctx, cancel := context.WithCancel(context.Background())
 
 	return &sendOnlyFolder{

lib/model/rwfolder.go

@@ -11,7 +11,6 @@ import (
 	"errors"
 	"fmt"
 	"math/rand"
-	"os"
 	"path/filepath"
 	"runtime"
 	"sort"
@@ -51,7 +50,7 @@ type copyBlocksState struct {
 }
 
 // Which filemode bits to preserve
-const retainBits = os.ModeSetgid | os.ModeSetuid | os.ModeSticky
+const retainBits = fs.ModeSetgid | fs.ModeSetuid | fs.ModeSticky
 
 var (
 	activity               = newDeviceActivity()
@@ -84,8 +83,7 @@ type sendReceiveFolder struct {
 	folder
 	config.FolderConfiguration
 
-	mtimeFS   *fs.MtimeFS
-	dir       string
+	fs        fs.Filesystem
 	versioner versioner.Versioner
 	sleep     time.Duration
 	pause     time.Duration
@@ -99,7 +97,7 @@ type sendReceiveFolder struct {
 	errorsMut sync.Mutex
 }
 
-func newSendReceiveFolder(model *Model, cfg config.FolderConfiguration, ver versioner.Versioner, mtimeFS *fs.MtimeFS) service {
+func newSendReceiveFolder(model *Model, cfg config.FolderConfiguration, ver versioner.Versioner, fs fs.Filesystem) service {
 	ctx, cancel := context.WithCancel(context.Background())
 
 	f := &sendReceiveFolder{
@@ -113,8 +111,7 @@ func newSendReceiveFolder(model *Model, cfg config.FolderConfiguration, ver vers
 		},
 		FolderConfiguration: cfg,
 
-		mtimeFS:   mtimeFS,
-		dir:       cfg.Path(),
+		fs:        fs,
 		versioner: ver,
 
 		queue:       newJobQueue(),
@@ -434,7 +431,7 @@ func (f *sendReceiveFolder) pullerIteration(ignores *ignore.Matcher) int {
 	for _, fi := range processDirectly {
 		// Verify that the thing we are handling lives inside a directory,
 		// and not a symlink or empty space.
-		if err := osutil.TraversesSymlink(f.dir, filepath.Dir(fi.Name)); err != nil {
+		if err := osutil.TraversesSymlink(f.fs, filepath.Dir(fi.Name)); err != nil {
 			f.newError(fi.Name, err)
 			continue
 		}
@@ -523,7 +520,7 @@ nextFile:
 
 		// Verify that the thing we are handling lives inside a directory,
 		// and not a symlink or empty space.
-		if err := osutil.TraversesSymlink(f.dir, filepath.Dir(fi.Name)); err != nil {
+		if err := osutil.TraversesSymlink(f.fs, filepath.Dir(fi.Name)); err != nil {
 			f.newError(fi.Name, err)
 			continue
 		}
@@ -610,12 +607,7 @@ func (f *sendReceiveFolder) handleDir(file protocol.FileInfo) {
 		})
 	}()
 
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-	mode := os.FileMode(file.Permissions & 0777)
+	mode := fs.FileMode(file.Permissions & 0777)
 	if f.ignorePermissions(file) {
 		mode = 0777
 	}
@@ -625,13 +617,13 @@ func (f *sendReceiveFolder) handleDir(file protocol.FileInfo) {
 		l.Debugf("need dir\n\t%v\n\t%v", file, curFile)
 	}
 
-	info, err := f.mtimeFS.Lstat(realName)
+	info, err := f.fs.Lstat(file.Name)
 	switch {
 	// There is already something under that name, but it's a file/link.
 	// Most likely a file/link is getting replaced with a directory.
 	// Remove the file/link and fall through to directory creation.
 	case err == nil && (!info.IsDir() || info.IsSymlink()):
-		err = osutil.InWritableDir(os.Remove, realName)
+		err = osutil.InWritableDir(f.fs.Remove, f.fs, file.Name)
 		if err != nil {
 			l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
 			f.newError(file.Name, err)
@@ -640,28 +632,28 @@ func (f *sendReceiveFolder) handleDir(file protocol.FileInfo) {
 		fallthrough
 	// The directory doesn't exist, so we create it with the right
 	// mode bits from the start.
-	case err != nil && os.IsNotExist(err):
+	case err != nil && fs.IsNotExist(err):
 		// We declare a function that acts on only the path name, so
 		// we can pass it to InWritableDir. We use a regular Mkdir and
 		// not MkdirAll because the parent should already exist.
 		mkdir := func(path string) error {
-			err = os.Mkdir(path, mode)
+			err = f.fs.Mkdir(path, mode)
 			if err != nil || f.ignorePermissions(file) {
 				return err
 			}
 
 			// Stat the directory so we can check its permissions.
-			info, err := f.mtimeFS.Lstat(path)
+			info, err := f.fs.Lstat(path)
 			if err != nil {
 				return err
 			}
 
 			// Mask for the bits we want to preserve and add them in to the
 			// directories permissions.
-			return os.Chmod(path, mode|(os.FileMode(info.Mode())&retainBits))
+			return f.fs.Chmod(path, mode|(info.Mode()&retainBits))
 		}
 
-		if err = osutil.InWritableDir(mkdir, realName); err == nil {
+		if err = osutil.InWritableDir(mkdir, f.fs, file.Name); err == nil {
 			f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
 		} else {
 			l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
@@ -681,7 +673,7 @@ func (f *sendReceiveFolder) handleDir(file protocol.FileInfo) {
 	// It's OK to change mode bits on stuff within non-writable directories.
 	if f.ignorePermissions(file) {
 		f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
-	} else if err := os.Chmod(realName, mode|(os.FileMode(info.Mode())&retainBits)); err == nil {
+	} else if err := f.fs.Chmod(file.Name, mode|(fs.FileMode(info.Mode())&retainBits)); err == nil {
 		f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleDir}
 	} else {
 		l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
@@ -712,12 +704,6 @@ func (f *sendReceiveFolder) handleSymlink(file protocol.FileInfo) {
 		})
 	}()
 
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-
 	if shouldDebug() {
 		curFile, _ := f.model.CurrentFolderFile(f.folderID, file.Name)
 		l.Debugf("need symlink\n\t%v\n\t%v", file, curFile)
@@ -732,11 +718,11 @@ func (f *sendReceiveFolder) handleSymlink(file protocol.FileInfo) {
 		return
 	}
 
-	if _, err = f.mtimeFS.Lstat(realName); err == nil {
+	if _, err = f.fs.Lstat(file.Name); err == nil {
 		// There is already something under that name. Remove it to replace
 		// with the symlink. This also handles the "change symlink type"
 		// path.
-		err = osutil.InWritableDir(os.Remove, realName)
+		err = osutil.InWritableDir(f.fs.Remove, f.fs, file.Name)
 		if err != nil {
 			l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
 			f.newError(file.Name, err)
@@ -747,10 +733,10 @@ func (f *sendReceiveFolder) handleSymlink(file protocol.FileInfo) {
 	// We declare a function that acts on only the path name, so
 	// we can pass it to InWritableDir.
 	createLink := func(path string) error {
-		return os.Symlink(file.SymlinkTarget, path)
+		return f.fs.CreateSymlink(file.SymlinkTarget, path)
 	}
 
-	if err = osutil.InWritableDir(createLink, realName); err == nil {
+	if err = osutil.InWritableDir(createLink, f.fs, file.Name); err == nil {
 		f.dbUpdates <- dbUpdateJob{file, dbUpdateHandleSymlink}
 	} else {
 		l.Infof("Puller (folder %q, dir %q): %v", f.folderID, file.Name, err)
@@ -781,31 +767,21 @@ func (f *sendReceiveFolder) deleteDir(file protocol.FileInfo, matcher *ignore.Ma
 		})
 	}()
 
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-
 	// Delete any temporary files lying around in the directory
-	dir, _ := os.Open(realName)
-	if dir != nil {
-		files, _ := dir.Readdirnames(-1)
-		for _, dirFile := range files {
-			fullDirFile := filepath.Join(file.Name, dirFile)
-			if ignore.IsTemporary(dirFile) || (matcher != nil &&
-				matcher.Match(fullDirFile).IsDeletable()) {
-				os.RemoveAll(filepath.Join(f.dir, fullDirFile))
-			}
+
+	files, _ := f.fs.DirNames(file.Name)
+	for _, dirFile := range files {
+		fullDirFile := filepath.Join(file.Name, dirFile)
+		if ignore.IsTemporary(dirFile) || (matcher != nil && matcher.Match(fullDirFile).IsDeletable()) {
+			f.fs.RemoveAll(fullDirFile)
 		}
-		dir.Close()
 	}
 
-	err = osutil.InWritableDir(os.Remove, realName)
-	if err == nil || os.IsNotExist(err) {
+	err = osutil.InWritableDir(f.fs.Remove, f.fs, file.Name)
+	if err == nil || fs.IsNotExist(err) {
 		// It was removed or it doesn't exist to start with
 		f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteDir}
-	} else if _, serr := f.mtimeFS.Lstat(realName); serr != nil && !os.IsPermission(serr) {
+	} else if _, serr := f.fs.Lstat(file.Name); serr != nil && !fs.IsPermission(serr) {
 		// We get an error just looking at the directory, and it's not a
 		// permission problem. Lets assume the error is in fact some variant
 		// of "file does not exist" (possibly expressed as some parent being a
@@ -840,12 +816,6 @@ func (f *sendReceiveFolder) deleteFile(file protocol.FileInfo) {
 		})
 	}()
 
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-
 	cur, ok := f.model.CurrentFolderFile(f.folderID, file.Name)
 	if ok && f.inConflict(cur.Version, file.Version) {
 		// There is a conflict here. Move the file to a conflict copy instead
@@ -854,17 +824,17 @@ func (f *sendReceiveFolder) deleteFile(file protocol.FileInfo) {
 		file.Version = file.Version.Merge(cur.Version)
 		err = osutil.InWritableDir(func(name string) error {
 			return f.moveForConflict(name, file.ModifiedBy.String())
-		}, realName)
-	} else if f.versioner != nil {
-		err = osutil.InWritableDir(f.versioner.Archive, realName)
+		}, f.fs, file.Name)
+	} else if f.versioner != nil && !cur.IsSymlink() {
+		err = osutil.InWritableDir(f.versioner.Archive, f.fs, file.Name)
 	} else {
-		err = osutil.InWritableDir(os.Remove, realName)
+		err = osutil.InWritableDir(f.fs.Remove, f.fs, file.Name)
 	}
 
-	if err == nil || os.IsNotExist(err) {
+	if err == nil || fs.IsNotExist(err) {
 		// It was removed or it doesn't exist to start with
 		f.dbUpdates <- dbUpdateJob{file, dbUpdateDeleteFile}
-	} else if _, serr := f.mtimeFS.Lstat(realName); serr != nil && !os.IsPermission(serr) {
+	} else if _, serr := f.fs.Lstat(file.Name); serr != nil && !fs.IsPermission(serr) {
 		// We get an error just looking at the file, and it's not a permission
 		// problem. Lets assume the error is in fact some variant of "file
 		// does not exist" (possibly expressed as some parent being a file and
@@ -915,24 +885,13 @@ func (f *sendReceiveFolder) renameFile(source, target protocol.FileInfo) {
 
 	l.Debugln(f, "taking rename shortcut", source.Name, "->", target.Name)
 
-	from, err := rootedJoinedPath(f.dir, source.Name)
-	if err != nil {
-		f.newError(source.Name, err)
-		return
-	}
-	to, err := rootedJoinedPath(f.dir, target.Name)
-	if err != nil {
-		f.newError(target.Name, err)
-		return
-	}
-
 	if f.versioner != nil {
-		err = osutil.Copy(from, to)
+		err = osutil.Copy(f.fs, source.Name, target.Name)
 		if err == nil {
-			err = osutil.InWritableDir(f.versioner.Archive, from)
+			err = osutil.InWritableDir(f.versioner.Archive, f.fs, source.Name)
 		}
 	} else {
-		err = osutil.TryRename(from, to)
+		err = osutil.TryRename(f.fs, source.Name, target.Name)
 	}
 
 	if err == nil {
@@ -955,7 +914,7 @@ func (f *sendReceiveFolder) renameFile(source, target protocol.FileInfo) {
 		// get rid of. Attempt to delete it instead so that we make *some*
 		// progress. The target is unhandled.
 
-		err = osutil.InWritableDir(os.Remove, from)
+		err = osutil.InWritableDir(f.fs.Remove, f.fs, source.Name)
 		if err != nil {
 			l.Infof("Puller (folder %q, file %q): delete %q after failed rename: %v", f.folderID, target.Name, source.Name, err)
 			f.newError(target.Name, err)
@@ -1041,38 +1000,7 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 		return
 	}
 
-	// Figure out the absolute filenames we need once and for all
-	tempName, err := rootedJoinedPath(f.dir, ignore.TempName(file.Name))
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return
-	}
-
-	if hasCurFile && !curFile.IsDirectory() && !curFile.IsSymlink() {
-		// Check that the file on disk is what we expect it to be according to
-		// the database. If there's a mismatch here, there might be local
-		// changes that we don't know about yet and we should scan before
-		// touching the file. If we can't stat the file we'll just pull it.
-		if info, err := f.mtimeFS.Lstat(realName); err == nil {
-			if !info.ModTime().Equal(curFile.ModTime()) || info.Size() != curFile.Size {
-				l.Debugln("file modified but not rescanned; not pulling:", realName)
-				// Scan() is synchronous (i.e. blocks until the scan is
-				// completed and returns an error), but a scan can't happen
-				// while we're in the puller routine. Request the scan in the
-				// background and it'll be handled when the current pulling
-				// sweep is complete. As we do retries, we'll queue the scan
-				// for this file up to ten times, but the last nine of those
-				// scans will be cheap...
-				go f.Scan([]string{file.Name})
-				return
-			}
-		}
-	}
+	tempName := ignore.TempName(file.Name)
 
 	scanner.PopulateOffsets(file.Blocks)
 
@@ -1082,7 +1010,7 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 
 	// Check for an old temporary file which might have some blocks we could
 	// reuse.
-	tempBlocks, err := scanner.HashFile(f.ctx, fs.DefaultFilesystem, tempName, protocol.BlockSize, nil, false)
+	tempBlocks, err := scanner.HashFile(f.ctx, f.fs, tempName, protocol.BlockSize, nil, false)
 	if err == nil {
 		// Check for any reusable blocks in the temp file
 		tempCopyBlocks, _ := scanner.BlockDiff(tempBlocks, file.Blocks)
@@ -1110,7 +1038,7 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 			// Otherwise, discard the file ourselves in order for the
 			// sharedpuller not to panic when it fails to exclusively create a
 			// file which already exists
-			osutil.InWritableDir(os.Remove, tempName)
+			osutil.InWritableDir(f.fs.Remove, f.fs, tempName)
 		}
 	} else {
 		// Copy the blocks, as we don't want to shuffle them on the FileInfo
@@ -1119,8 +1047,8 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 	}
 
 	if f.MinDiskFree.BaseValue() > 0 {
-		if free, err := osutil.DiskFreeBytes(f.dir); err == nil && free < blocksSize {
-			l.Warnf(`Folder "%s": insufficient disk space in %s for %s: have %.2f MiB, need %.2f MiB`, f.folderID, f.dir, file.Name, float64(free)/1024/1024, float64(blocksSize)/1024/1024)
+		if usage, err := f.fs.Usage("."); err == nil && usage.Free < blocksSize {
+			l.Warnf(`Folder "%s": insufficient disk space in %s for %s: have %.2f MiB, need %.2f MiB`, f.folderID, f.fs.URI(), file.Name, float64(usage.Free)/1024/1024, float64(blocksSize)/1024/1024)
 			f.newError(file.Name, errors.New("insufficient space"))
 			return
 		}
@@ -1141,9 +1069,10 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 
 	s := sharedPullerState{
 		file:             file,
+		fs:               f.fs,
 		folder:           f.folderID,
 		tempName:         tempName,
-		realName:         realName,
+		realName:         file.Name,
 		copyTotal:        len(blocks),
 		copyNeeded:       len(blocks),
 		reused:           len(reused),
@@ -1151,7 +1080,8 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 		available:        reused,
 		availableUpdated: time.Now(),
 		ignorePerms:      f.ignorePermissions(file),
-		version:          curFile.Version,
+		hasCurFile:       hasCurFile,
+		curFile:          curFile,
 		mut:              sync.NewRWMutex(),
 		sparse:           !f.DisableSparseFiles,
 		created:          time.Now(),
@@ -1170,20 +1100,15 @@ func (f *sendReceiveFolder) handleFile(file protocol.FileInfo, copyChan chan<- c
 // shortcutFile sets file mode and modification time, when that's the only
 // thing that has changed.
 func (f *sendReceiveFolder) shortcutFile(file protocol.FileInfo) error {
-	realName, err := rootedJoinedPath(f.dir, file.Name)
-	if err != nil {
-		f.newError(file.Name, err)
-		return err
-	}
 	if !f.ignorePermissions(file) {
-		if err := os.Chmod(realName, os.FileMode(file.Permissions&0777)); err != nil {
+		if err := f.fs.Chmod(file.Name, fs.FileMode(file.Permissions&0777)); err != nil {
 			l.Infof("Puller (folder %q, file %q): shortcut: chmod: %v", f.folderID, file.Name, err)
 			f.newError(file.Name, err)
 			return err
 		}
 	}
 
-	f.mtimeFS.Chtimes(realName, file.ModTime(), file.ModTime()) // never fails
+	f.fs.Chtimes(file.Name, file.ModTime(), file.ModTime()) // never fails
 
 	// This may have been a conflict. We should merge the version vectors so
 	// that our clock doesn't move backwards.
@@ -1211,15 +1136,16 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 			f.model.progressEmitter.Register(state.sharedPullerState)
 		}
 
-		folderRoots := make(map[string]string)
+		folderFilesystems := make(map[string]fs.Filesystem)
 		var folders []string
 		f.model.fmut.RLock()
 		for folder, cfg := range f.model.folderCfgs {
-			folderRoots[folder] = cfg.Path()
+			folderFilesystems[folder] = cfg.Filesystem()
 			folders = append(folders, folder)
 		}
 		f.model.fmut.RUnlock()
 
+		var file fs.File
 		var weakHashFinder *weakhash.Finder
 
 		if weakhash.Enabled {
@@ -1237,9 +1163,12 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 				}
 
 				if len(hashesToFind) > 0 {
-					weakHashFinder, err = weakhash.NewFinder(state.realName, protocol.BlockSize, hashesToFind)
-					if err != nil {
-						l.Debugln("weak hasher", err)
+					file, err = f.fs.Open(state.file.Name)
+					if err == nil {
+						weakHashFinder, err = weakhash.NewFinder(file, protocol.BlockSize, hashesToFind)
+						if err != nil {
+							l.Debugln("weak hasher", err)
+						}
 					}
 				} else {
 					l.Debugf("not weak hashing %s. file did not contain any weak hashes", state.file.Name)
@@ -1289,12 +1218,9 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 			}
 
 			if !found {
-				found = f.model.finder.Iterate(folders, block.Hash, func(folder, file string, index int32) bool {
-					inFile, err := rootedJoinedPath(folderRoots[folder], file)
-					if err != nil {
-						return false
-					}
-					fd, err := os.Open(inFile)
+				found = f.model.finder.Iterate(folders, block.Hash, func(folder, path string, index int32) bool {
+					fs := folderFilesystems[folder]
+					fd, err := fs.Open(path)
 					if err != nil {
 						return false
 					}
@@ -1308,8 +1234,8 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 					hash, err := scanner.VerifyBuffer(buf, block)
 					if err != nil {
 						if hash != nil {
-							l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, file, index, block.Hash, hash)
-							err = f.model.finder.Fix(folder, file, index, block.Hash, hash)
+							l.Debugf("Finder block mismatch in %s:%s:%d expected %q got %q", folder, path, index, block.Hash, hash)
+							err = f.model.finder.Fix(folder, path, index, block.Hash, hash)
 							if err != nil {
 								l.Warnln("finder fix:", err)
 							}
@@ -1323,7 +1249,7 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 					if err != nil {
 						state.fail("dst write", err)
 					}
-					if file == state.file.Name {
+					if path == state.file.Name {
 						state.copiedFromOrigin()
 					}
 					return true
@@ -1345,7 +1271,12 @@ func (f *sendReceiveFolder) copierRoutine(in <-chan copyBlocksState, pullChan ch
 				state.copyDone(block)
 			}
 		}
-		weakHashFinder.Close()
+		if file != nil {
+			// os.File used to return invalid argument if nil.
+			// fs.File panics as it's an interface.
+			file.Close()
+		}
+
 		out <- state.sharedPullerState
 	}
 }
@@ -1426,15 +1357,45 @@ func (f *sendReceiveFolder) pullerRoutine(in <-chan pullBlockState, out chan<- *
 func (f *sendReceiveFolder) performFinish(state *sharedPullerState) error {
 	// Set the correct permission bits on the new file
 	if !f.ignorePermissions(state.file) {
-		if err := os.Chmod(state.tempName, os.FileMode(state.file.Permissions&0777)); err != nil {
+		if err := f.fs.Chmod(state.tempName, fs.FileMode(state.file.Permissions&0777)); err != nil {
 			return err
 		}
 	}
 
-	if stat, err := f.mtimeFS.Lstat(state.realName); err == nil {
+	if stat, err := f.fs.Lstat(state.file.Name); err == nil {
 		// There is an old file or directory already in place. We need to
 		// handle that.
 
+		curMode := uint32(stat.Mode())
+		if runtime.GOOS == "windows" && osutil.IsWindowsExecutable(state.file.Name) {
+			curMode |= 0111
+		}
+
+		// Check that the file on disk is what we expect it to be according to
+		// the database. If there's a mismatch here, there might be local
+		// changes that we don't know about yet and we should scan before
+		// touching the file.
+		// There is also a case where we think the file should be there, but
+		// it was removed, which is a conflict, yet creations always wins when
+		// competing with a deletion, so no need to handle that specially.
+		switch {
+		// The file reappeared from nowhere, or mtime/size has changed, fallthrough -> rescan.
+		case !state.hasCurFile || !stat.ModTime().Equal(state.curFile.ModTime()) || stat.Size() != state.curFile.Size:
+			fallthrough
+		// Permissions have changed, means the file has changed, rescan.
+		case !f.ignorePermissions(state.curFile) && state.curFile.HasPermissionBits() && !scanner.PermsEqual(state.curFile.Permissions, curMode):
+			l.Debugln("file modified but not rescanned; not finishing:", state.curFile.Name)
+			// Scan() is synchronous (i.e. blocks until the scan is
+			// completed and returns an error), but a scan can't happen
+			// while we're in the puller routine. Request the scan in the
+			// background and it'll be handled when the current pulling
+			// sweep is complete. As we do retries, we'll queue the scan
+			// for this file up to ten times, but the last nine of those
+			// scans will be cheap...
+			go f.Scan([]string{state.curFile.Name})
+			return nil
+		}
+
 		switch {
 		case stat.IsDir() || stat.IsSymlink():
 			// It's a directory or a symlink. These are not versioned or
@@ -1445,30 +1406,30 @@ func (f *sendReceiveFolder) performFinish(state *sharedPullerState) error {
 			// and future hard ignores before attempting a directory delete.
 			// Should share code with f.deletDir().
 
-			if err = osutil.InWritableDir(os.Remove, state.realName); err != nil {
+			if err = osutil.InWritableDir(f.fs.Remove, f.fs, state.file.Name); err != nil {
 				return err
 			}
 
-		case f.inConflict(state.version, state.file.Version):
+		case f.inConflict(state.curFile.Version, state.file.Version):
 			// The new file has been changed in conflict with the existing one. We
 			// should file it away as a conflict instead of just removing or
 			// archiving. Also merge with the version vector we had, to indicate
 			// we have resolved the conflict.
 
-			state.file.Version = state.file.Version.Merge(state.version)
+			state.file.Version = state.file.Version.Merge(state.curFile.Version)
 			err = osutil.InWritableDir(func(name string) error {
 				return f.moveForConflict(name, state.file.ModifiedBy.String())
-			}, state.realName)
+			}, f.fs, state.file.Name)
 			if err != nil {
 				return err
 			}
 
-		case f.versioner != nil:
+		case f.versioner != nil && !state.file.IsSymlink():
 			// If we should use versioning, let the versioner archive the old
 			// file before we replace it. Archiving a non-existent file is not
 			// an error.
 
-			if err = f.versioner.Archive(state.realName); err != nil {
+			if err = f.versioner.Archive(state.file.Name); err != nil {
 				return err
 			}
 		}
@@ -1476,12 +1437,12 @@ func (f *sendReceiveFolder) performFinish(state *sharedPullerState) error {
 
 	// Replace the original content with the new one. If it didn't work,
 	// leave the temp file in place for reuse.
-	if err := osutil.TryRename(state.tempName, state.realName); err != nil {
+	if err := osutil.TryRename(f.fs, state.tempName, state.file.Name); err != nil {
 		return err
 	}
 
 	// Set the correct timestamp on the new file
-	f.mtimeFS.Chtimes(state.realName, state.file.ModTime(), state.file.ModTime()) // never fails
+	f.fs.Chtimes(state.file.Name, state.file.ModTime(), state.file.ModTime()) // never fails
 
 	// Record the updated file in the index
 	f.dbUpdates <- dbUpdateJob{state.file, dbUpdateHandleFile}
@@ -1540,26 +1501,7 @@ func (f *sendReceiveFolder) dbUpdaterRoutine() {
 	tick := time.NewTicker(maxBatchTime)
 	defer tick.Stop()
 
-	var changedFiles []string
-	var changedDirs []string
-	if f.Fsync {
-		changedFiles = make([]string, 0, maxBatchSize)
-		changedDirs = make([]string, 0, maxBatchSize)
-	}
-
-	syncFilesOnce := func(files []string, syncFn func(string) error) {
-		sort.Strings(files)
-		var lastFile string
-		for _, file := range files {
-			if lastFile == file {
-				continue
-			}
-			lastFile = file
-			if err := syncFn(file); err != nil {
-				l.Infof("fsync %q failed: %v", file, err)
-			}
-		}
-	}
+	changedDirs := make(map[string]struct{})
 
 	handleBatch := func() {
 		found := false
@@ -1567,20 +1509,16 @@ func (f *sendReceiveFolder) dbUpdaterRoutine() {
 
 		for _, job := range batch {
 			files = append(files, job.file)
-			if f.Fsync {
-				// collect changed files and dirs
-				switch job.jobType {
-				case dbUpdateHandleFile, dbUpdateShortcutFile:
-					changedFiles = append(changedFiles, filepath.Join(f.dir, job.file.Name))
-				case dbUpdateHandleDir:
-					changedDirs = append(changedDirs, filepath.Join(f.dir, job.file.Name))
-				case dbUpdateHandleSymlink:
-					// fsyncing symlinks is only supported by MacOS, ignore
-				}
-				if job.jobType != dbUpdateShortcutFile {
-					changedDirs = append(changedDirs, filepath.Dir(filepath.Join(f.dir, job.file.Name)))
-				}
+
+			switch job.jobType {
+			case dbUpdateHandleFile, dbUpdateShortcutFile:
+				changedDirs[filepath.Dir(job.file.Name)] = struct{}{}
+			case dbUpdateHandleDir:
+				changedDirs[job.file.Name] = struct{}{}
+			case dbUpdateHandleSymlink:
+				// fsyncing symlinks is only supported by MacOS, ignore
 			}
+
 			if job.file.IsInvalid() || (job.file.IsDirectory() && !job.file.IsSymlink()) {
 				continue
 			}
@@ -1593,12 +1531,18 @@ func (f *sendReceiveFolder) dbUpdaterRoutine() {
 			lastFile = job.file
 		}
 
-		if f.Fsync {
-			// sync files and dirs to disk
-			syncFilesOnce(changedFiles, osutil.SyncFile)
-			changedFiles = changedFiles[:0]
-			syncFilesOnce(changedDirs, osutil.SyncDir)
-			changedDirs = changedDirs[:0]
+		// sync directories
+		for dir := range changedDirs {
+			delete(changedDirs, dir)
+			fd, err := f.fs.Open(dir)
+			if err != nil {
+				l.Infof("fsync %q failed: %v", dir, err)
+				continue
+			}
+			if err := fd.Sync(); err != nil {
+				l.Infof("fsync %q failed: %v", dir, err)
+			}
+			fd.Close()
 		}
 
 		// All updates to file/folder objects that originated remotely
@@ -1669,14 +1613,14 @@ func removeAvailability(availabilities []Availability, availability Availability
 func (f *sendReceiveFolder) moveForConflict(name string, lastModBy string) error {
 	if strings.Contains(filepath.Base(name), ".sync-conflict-") {
 		l.Infoln("Conflict for", name, "which is already a conflict copy; not copying again.")
-		if err := os.Remove(name); err != nil && !os.IsNotExist(err) {
+		if err := f.fs.Remove(name); err != nil && !fs.IsNotExist(err) {
 			return err
 		}
 		return nil
 	}
 
 	if f.MaxConflicts == 0 {
-		if err := os.Remove(name); err != nil && !os.IsNotExist(err) {
+		if err := f.fs.Remove(name); err != nil && !fs.IsNotExist(err) {
 			return err
 		}
 		return nil
@@ -1685,8 +1629,8 @@ func (f *sendReceiveFolder) moveForConflict(name string, lastModBy string) error
 	ext := filepath.Ext(name)
 	withoutExt := name[:len(name)-len(ext)]
 	newName := withoutExt + time.Now().Format(".sync-conflict-20060102-150405-") + lastModBy + ext
-	err := os.Rename(name, newName)
-	if os.IsNotExist(err) {
+	err := f.fs.Rename(name, newName)
+	if fs.IsNotExist(err) {
 		// We were supposed to move a file away but it does not exist. Either
 		// the user has already moved it away, or the conflict was between a
 		// remote modification and a local delete. In either way it does not
@@ -1694,11 +1638,11 @@ func (f *sendReceiveFolder) moveForConflict(name string, lastModBy string) error
 		err = nil
 	}
 	if f.MaxConflicts > -1 {
-		matches, gerr := osutil.Glob(withoutExt + ".sync-conflict-????????-??????*" + ext)
+		matches, gerr := f.fs.Glob(withoutExt + ".sync-conflict-????????-??????*" + ext)
 		if gerr == nil && len(matches) > f.MaxConflicts {
 			sort.Sort(sort.Reverse(sort.StringSlice(matches)))
 			for _, match := range matches[f.MaxConflicts:] {
-				gerr = os.Remove(match)
+				gerr = f.fs.Remove(match)
 				if gerr != nil {
 					l.Debugln(f, "removing extra conflict", gerr)
 				}
@@ -1772,7 +1716,7 @@ func fileValid(file db.FileIntf) error {
 		return errSymlinksUnsupported
 
 	case runtime.GOOS == "windows" && windowsInvalidFilename(file.FileName()):
-		return errInvalidFilename
+		return fs.ErrInvalidFilename
 	}
 
 	return nil
@@ -1821,7 +1765,7 @@ func (l byComponentCount) Swap(a, b int) {
 func componentCount(name string) int {
 	count := 0
 	for _, codepoint := range name {
-		if codepoint == os.PathSeparator {
+		if codepoint == fs.PathSeparator {
 			count++
 		}
 	}

lib/model/rwfolder_test.go

@@ -87,8 +87,7 @@ func setUpSendReceiveFolder(model *Model) *sendReceiveFolder {
 			ctx:                 context.TODO(),
 		},
 
-		mtimeFS:   fs.NewMtimeFS(fs.DefaultFilesystem, db.NewNamespacedKV(model.db, "mtime")),
-		dir:       "testdata",
+		fs:        fs.NewMtimeFS(fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"), db.NewNamespacedKV(model.db, "mtime")),
 		queue:     newJobQueue(),
 		errors:    make(map[string]string),
 		errorsMut: sync.NewMutex(),
@@ -246,7 +245,7 @@ func TestCopierFinder(t *testing.T) {
 	}
 
 	// Verify that the fetched blocks have actually been written to the temp file
-	blks, err := scanner.HashFile(context.TODO(), fs.DefaultFilesystem, tempFile, protocol.BlockSize, nil, false)
+	blks, err := scanner.HashFile(context.TODO(), fs.NewFilesystem(fs.FilesystemTypeBasic, "."), tempFile, protocol.BlockSize, nil, false)
 	if err != nil {
 		t.Log(err)
 	}

lib/model/sharedpullerstate.go

@@ -8,10 +8,10 @@ package model
 
 import (
 	"io"
-	"os"
 	"path/filepath"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/sync"
 )
@@ -21,18 +21,20 @@ import (
 type sharedPullerState struct {
 	// Immutable, does not require locking
 	file        protocol.FileInfo // The new file (desired end state)
+	fs          fs.Filesystem
 	folder      string
 	tempName    string
 	realName    string
 	reused      int // Number of blocks reused from temporary file
 	ignorePerms bool
-	version     protocol.Vector // The current (old) version
+	hasCurFile  bool              // Whether curFile is set
+	curFile     protocol.FileInfo // The file as it exists now in our database
 	sparse      bool
 	created     time.Time
 
 	// Mutable, must be locked for access
 	err               error        // The first error we hit
-	fd                *os.File     // The fd of the temp file
+	fd                fs.File      // The fd of the temp file
 	copyTotal         int          // Total number of copy actions for the whole job
 	pullTotal         int          // Total number of pull actions for the whole job
 	copyOrigin        int          // Number of blocks copied from the original file
@@ -92,8 +94,8 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 	// osutil.InWritableDir except we need to do more stuff so we duplicate it
 	// here.
 	dir := filepath.Dir(s.tempName)
-	if info, err := os.Stat(dir); err != nil {
-		if os.IsNotExist(err) {
+	if info, err := s.fs.Stat(dir); err != nil {
+		if fs.IsNotExist(err) {
 			// XXX: This works around a bug elsewhere, a race condition when
 			// things are deleted while being synced. However that happens, we
 			// end up with a directory for "foo" with the delete bit, but a
@@ -103,7 +105,7 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 			// next scan it'll be found and the delete bit on it is removed.
 			// The user can then clean up as they like...
 			l.Infoln("Resurrecting directory", dir)
-			if err := os.MkdirAll(dir, 0755); err != nil {
+			if err := s.fs.MkdirAll(dir, 0755); err != nil {
 				s.failLocked("resurrect dir", err)
 				return nil, err
 			}
@@ -112,10 +114,10 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 			return nil, err
 		}
 	} else if info.Mode()&0200 == 0 {
-		err := os.Chmod(dir, 0755)
+		err := s.fs.Chmod(dir, 0755)
 		if !s.ignorePerms && err == nil {
 			defer func() {
-				err := os.Chmod(dir, info.Mode().Perm())
+				err := s.fs.Chmod(dir, info.Mode()&fs.ModePerm)
 				if err != nil {
 					panic(err)
 				}
@@ -128,7 +130,7 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 	// permissions will be set to the final value later, but in the meantime
 	// we don't want to have a temporary file with looser permissions than
 	// the final outcome.
-	mode := os.FileMode(s.file.Permissions) | 0600
+	mode := fs.FileMode(s.file.Permissions) | 0600
 	if s.ignorePerms {
 		// When ignorePerms is set we use a very permissive mode and let the
 		// system umask filter it.
@@ -137,9 +139,9 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 
 	// Attempt to create the temp file
 	// RDWR because of issue #2994.
-	flags := os.O_RDWR
+	flags := fs.OptReadWrite
 	if s.reused == 0 {
-		flags |= os.O_CREATE | os.O_EXCL
+		flags |= fs.OptCreate | fs.OptExclusive
 	} else if !s.ignorePerms {
 		// With sufficiently bad luck when exiting or crashing, we may have
 		// had time to chmod the temp file to read only state but not yet
@@ -151,12 +153,12 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 		// already and make no modification, as we would otherwise override
 		// what the umask dictates.
 
-		if err := os.Chmod(s.tempName, mode); err != nil {
+		if err := s.fs.Chmod(s.tempName, mode); err != nil {
 			s.failLocked("dst create chmod", err)
 			return nil, err
 		}
 	}
-	fd, err := os.OpenFile(s.tempName, flags, mode)
+	fd, err := s.fs.OpenFile(s.tempName, flags, mode)
 	if err != nil {
 		s.failLocked("dst create", err)
 		return nil, err
@@ -180,7 +182,7 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 }
 
 // sourceFile opens the existing source file for reading
-func (s *sharedPullerState) sourceFile() (*os.File, error) {
+func (s *sharedPullerState) sourceFile() (fs.File, error) {
 	s.mut.Lock()
 	defer s.mut.Unlock()
 
@@ -190,7 +192,7 @@ func (s *sharedPullerState) sourceFile() (*os.File, error) {
 	}
 
 	// Attempt to open the existing file
-	fd, err := os.Open(s.realName)
+	fd, err := s.fs.Open(s.realName)
 	if err != nil {
 		s.failLocked("src open", err)
 		return nil, err
@@ -292,9 +294,12 @@ func (s *sharedPullerState) finalClose() (bool, error) {
 	}
 
 	if s.fd != nil {
+		// This is our error if we weren't errored before. Otherwise we
+		// keep the earlier error.
+		if fsyncErr := s.fd.Sync(); fsyncErr != nil && s.err == nil {
+			s.err = fsyncErr
+		}
 		if closeErr := s.fd.Close(); closeErr != nil && s.err == nil {
-			// This is our error if we weren't errored before. Otherwise we
-			// keep the earlier error.
 			s.err = closeErr
 		}
 		s.fd = nil

lib/model/sharedpullerstate_test.go

@@ -10,12 +10,14 @@ import (
 	"os"
 	"testing"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/sync"
 )
 
 func TestSourceFileOK(t *testing.T) {
 	s := sharedPullerState{
-		realName: "testdata/foo",
+		fs:       fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
+		realName: "foo",
 		mut:      sync.NewRWMutex(),
 	}
 
@@ -47,6 +49,7 @@ func TestSourceFileOK(t *testing.T) {
 
 func TestSourceFileBad(t *testing.T) {
 	s := sharedPullerState{
+		fs:       fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
 		realName: "nonexistent",
 		mut:      sync.NewRWMutex(),
 	}
@@ -73,7 +76,8 @@ func TestReadOnlyDir(t *testing.T) {
 	}()
 
 	s := sharedPullerState{
-		tempName: "testdata/read_only_dir/.temp_name",
+		fs:       fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
+		tempName: "read_only_dir/.temp_name",
 		mut:      sync.NewRWMutex(),
 	}
 

lib/osutil/atomic.go

@@ -8,10 +8,10 @@ package osutil
 
 import (
 	"errors"
-	"io/ioutil"
-	"os"
 	"path/filepath"
 	"runtime"
+
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 var (
@@ -25,7 +25,8 @@ var (
 // returned on Close, so a lazy user can ignore errors until Close.
 type AtomicWriter struct {
 	path string
-	next *os.File
+	next fs.File
+	fs   fs.Filesystem
 	err  error
 }
 
@@ -33,11 +34,19 @@ type AtomicWriter struct {
 // instead of the given name. The file is created with secure (0600)
 // permissions.
 func CreateAtomic(path string) (*AtomicWriter, error) {
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, filepath.Dir(path))
+	return CreateAtomicFilesystem(fs, filepath.Base(path))
+}
+
+// CreateAtomicFilesystem is like os.Create, except a temporary file name is used
+// instead of the given name. The file is created with secure (0600)
+// permissions.
+func CreateAtomicFilesystem(filesystem fs.Filesystem, path string) (*AtomicWriter, error) {
 	// The security of this depends on the tempfile having secure
 	// permissions, 0600, from the beginning. This is what ioutil.TempFile
 	// does. We have a test that verifies that that is the case, should this
 	// ever change in the standard library in the future.
-	fd, err := ioutil.TempFile(filepath.Dir(path), TempPrefix)
+	fd, err := TempFile(filesystem, filepath.Dir(path), TempPrefix)
 	if err != nil {
 		return nil, err
 	}
@@ -45,6 +54,7 @@ func CreateAtomic(path string) (*AtomicWriter, error) {
 	w := &AtomicWriter{
 		path: path,
 		next: fd,
+		fs:   filesystem,
 	}
 
 	return w, nil
@@ -71,7 +81,7 @@ func (w *AtomicWriter) Close() error {
 	}
 
 	// Try to not leave temp file around, but ignore error.
-	defer os.Remove(w.next.Name())
+	defer w.fs.Remove(w.next.Name())
 
 	if err := w.next.Sync(); err != nil {
 		w.err = err
@@ -88,17 +98,21 @@ func (w *AtomicWriter) Close() error {
 	// either. Return this error because it may be more informative. On non-
 	// Windows we want the atomic rename behavior so we don't attempt remove.
 	if runtime.GOOS == "windows" {
-		if err := os.Remove(w.path); err != nil && !os.IsNotExist(err) {
+		if err := w.fs.Remove(w.path); err != nil && !fs.IsNotExist(err) {
 			return err
 		}
 	}
 
-	if err := os.Rename(w.next.Name(), w.path); err != nil {
+	if err := w.fs.Rename(w.next.Name(), w.path); err != nil {
 		w.err = err
 		return err
 	}
 
-	SyncDir(filepath.Dir(w.next.Name()))
+	// fsync the directory too
+	if fd, err := w.fs.Open(filepath.Dir(w.next.Name())); err == nil {
+		fd.Sync()
+		fd.Close()
+	}
 
 	// Set w.err to return appropriately for any future operations.
 	w.err = ErrClosed

lib/osutil/fsroots_unix.go

@@ -1,13 +0,0 @@
-// Copyright (C) 2016 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build !windows
-
-package osutil
-
-func GetFilesystemRoots() ([]string, error) {
-	return []string{"/"}, nil
-}

lib/osutil/fsroots_windows.go

@@ -1,46 +0,0 @@
-// Copyright (C) 2016 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build windows
-
-package osutil
-
-import (
-	"bytes"
-	"fmt"
-	"syscall"
-	"unsafe"
-)
-
-func GetFilesystemRoots() ([]string, error) {
-	kernel32, err := syscall.LoadDLL("kernel32.dll")
-	if err != nil {
-		return nil, err
-	}
-	getLogicalDriveStringsHandle, err := kernel32.FindProc("GetLogicalDriveStringsA")
-	if err != nil {
-		return nil, err
-	}
-
-	buffer := [1024]byte{}
-	bufferSize := uint32(len(buffer))
-
-	hr, _, _ := getLogicalDriveStringsHandle.Call(uintptr(unsafe.Pointer(&bufferSize)), uintptr(unsafe.Pointer(&buffer)))
-	if hr == 0 {
-		return nil, fmt.Errorf("Syscall failed")
-	}
-
-	var drives []string
-	parts := bytes.Split(buffer[:], []byte{0})
-	for _, part := range parts {
-		if len(part) == 0 {
-			break
-		}
-		drives = append(drives, string(part))
-	}
-
-	return drives, nil
-}

lib/osutil/glob_unix.go

@@ -1,17 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build !windows
-
-package osutil
-
-import (
-	"path/filepath"
-)
-
-func Glob(pattern string) (matches []string, err error) {
-	return filepath.Glob(pattern)
-}

lib/osutil/glob_windows.go

@@ -1,96 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build windows
-
-package osutil
-
-import (
-	"os"
-	"path/filepath"
-	"runtime"
-	"sort"
-	"strings"
-)
-
-// Glob implements filepath.Glob, but works with Windows long path prefixes.
-// Deals with https://github.com/golang/go/issues/10577
-func Glob(pattern string) (matches []string, err error) {
-	if !hasMeta(pattern) {
-		if _, err = os.Lstat(pattern); err != nil {
-			return nil, nil
-		}
-		return []string{pattern}, nil
-	}
-
-	dir, file := filepath.Split(filepath.Clean(pattern))
-	switch dir {
-	case "":
-		dir = "."
-	case string(filepath.Separator):
-		// nothing
-	default:
-		if runtime.GOOS != "windows" || len(dir) < 2 || dir[len(dir)-2] != ':' {
-			dir = dir[0 : len(dir)-1] // chop off trailing separator, if it's not after the drive letter
-		}
-	}
-
-	if !hasMeta(dir) {
-		return glob(dir, file, nil)
-	}
-
-	var m []string
-	m, err = Glob(dir)
-	if err != nil {
-		return
-	}
-	for _, d := range m {
-		matches, err = glob(d, file, matches)
-		if err != nil {
-			return
-		}
-	}
-	return
-}
-
-func hasMeta(path string) bool {
-	// Strip off Windows long path prefix if it exists.
-	if strings.HasPrefix(path, "\\\\?\\") {
-		path = path[4:]
-	}
-	// TODO(niemeyer): Should other magic characters be added here?
-	return strings.IndexAny(path, "*?[") >= 0
-}
-
-func glob(dir, pattern string, matches []string) (m []string, e error) {
-	m = matches
-	fi, err := os.Stat(dir)
-	if err != nil {
-		return
-	}
-	if !fi.IsDir() {
-		return
-	}
-	d, err := os.Open(dir)
-	if err != nil {
-		return
-	}
-	defer d.Close()
-
-	names, _ := d.Readdirnames(-1)
-	sort.Strings(names)
-
-	for _, n := range names {
-		matched, err := filepath.Match(pattern, n)
-		if err != nil {
-			return m, err
-		}
-		if matched {
-			m = append(m, filepath.Join(dir, n))
-		}
-	}
-	return
-}

lib/osutil/glob_windows_test.go

@@ -1,29 +0,0 @@
-// Copyright (C) 2014 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build windows
-
-package osutil_test
-
-import (
-	"testing"
-
-	"github.com/syncthing/syncthing/lib/osutil"
-)
-
-func TestGlob(t *testing.T) {
-	testcases := []string{
-		`C:\*`,
-		`\\?\C:\*`,
-		`\\?\C:\Users`,
-		`\\?\\\?\C:\Users`,
-	}
-	for _, tc := range testcases {
-		if _, err := osutil.Glob(tc); err != nil {
-			t.Fatalf("pattern %s failed: %v", tc, err)
-		}
-	}
-}

lib/osutil/hidden_unix.go

@@ -8,12 +8,4 @@
 
 package osutil
 
-func HideFile(path string) error {
-	return nil
-}
-
-func ShowFile(path string) error {
-	return nil
-}
-
 func HideConsole() {}

lib/osutil/hidden_windows.go

@@ -10,36 +10,6 @@ package osutil
 
 import "syscall"
 
-func HideFile(path string) error {
-	p, err := syscall.UTF16PtrFromString(path)
-	if err != nil {
-		return err
-	}
-
-	attrs, err := syscall.GetFileAttributes(p)
-	if err != nil {
-		return err
-	}
-
-	attrs |= syscall.FILE_ATTRIBUTE_HIDDEN
-	return syscall.SetFileAttributes(p, attrs)
-}
-
-func ShowFile(path string) error {
-	p, err := syscall.UTF16PtrFromString(path)
-	if err != nil {
-		return err
-	}
-
-	attrs, err := syscall.GetFileAttributes(p)
-	if err != nil {
-		return err
-	}
-
-	attrs &^= syscall.FILE_ATTRIBUTE_HIDDEN
-	return syscall.SetFileAttributes(p, attrs)
-}
-
 func HideConsole() {
 	getConsoleWindow := syscall.NewLazyDLL("kernel32.dll").NewProc("GetConsoleWindow")
 	showWindow := syscall.NewLazyDLL("user32.dll").NewProc("ShowWindow")

lib/osutil/lstat_broken.go

@@ -1,29 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build linux android
-
-package osutil
-
-import (
-	"os"
-	"syscall"
-	"time"
-)
-
-// Lstat is like os.Lstat, except lobotomized for Android. See
-// https://forum.syncthing.net/t/2395
-func Lstat(name string) (fi os.FileInfo, err error) {
-	for i := 0; i < 10; i++ { // We have to draw the line somewhere
-		fi, err = os.Lstat(name)
-		if err, ok := err.(*os.PathError); ok && err.Err == syscall.EINTR {
-			time.Sleep(time.Duration(i+1) * time.Millisecond)
-			continue
-		}
-		return
-	}
-	return
-}

lib/osutil/lstat_ok.go

@@ -1,15 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build !linux,!android
-
-package osutil
-
-import "os"
-
-func Lstat(name string) (fi os.FileInfo, err error) {
-	return os.Lstat(name)
-}

lib/osutil/mkdirall.go

@@ -1,17 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-// +build !windows
-
-package osutil
-
-import (
-	"os"
-)
-
-func MkdirAll(path string, perm os.FileMode) error {
-	return os.MkdirAll(path, perm)
-}

lib/osutil/mkdirall_windows.go

@@ -1,93 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//   * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//   * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//   * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-//
-// Modified by Zillode to fix https://github.com/syncthing/syncthing/issues/1822
-// Sync with https://github.com/golang/go/blob/master/src/os/path.go
-// See https://github.com/golang/go/issues/10900
-
-package osutil
-
-import (
-	"os"
-	"path/filepath"
-	"syscall"
-)
-
-// MkdirAll creates a directory named path, along with any necessary parents,
-// and returns nil, or else returns an error.
-// The permission bits perm are used for all directories that MkdirAll creates.
-// If path is already a directory, MkdirAll does nothing and returns nil.
-func MkdirAll(path string, perm os.FileMode) error {
-	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
-	dir, err := os.Stat(path)
-	if err == nil {
-		if dir.IsDir() {
-			return nil
-		}
-		return &os.PathError{
-			Op:   "mkdir",
-			Path: path,
-			Err:  syscall.ENOTDIR,
-		}
-	}
-
-	// Slow path: make sure parent exists and then call Mkdir for path.
-	i := len(path)
-	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
-		i--
-	}
-
-	j := i
-	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
-		j--
-	}
-
-	if j > 1 {
-		// Create parent
-		parent := path[0 : j-1]
-		if parent != filepath.VolumeName(parent) {
-			err = MkdirAll(parent, perm)
-			if err != nil {
-				return err
-			}
-		}
-	}
-
-	// Parent now exists; invoke Mkdir and use its result.
-	err = os.Mkdir(path, perm)
-	if err != nil {
-		// Handle arguments like "foo/." by
-		// double-checking that directory doesn't exist.
-		dir, err1 := os.Lstat(path)
-		if err1 == nil && dir.IsDir() {
-			return nil
-		}
-		return err
-	}
-	return nil
-}

lib/osutil/net.go

@@ -0,0 +1,56 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package osutil
+
+import (
+	"bytes"
+	"net"
+)
+
+// ResolveInterfaceAddresses returns available addresses of the given network
+// type for a given interface.
+func ResolveInterfaceAddresses(network, nameOrMac string) []string {
+	intf, err := net.InterfaceByName(nameOrMac)
+	if err == nil {
+		return interfaceAddresses(network, intf)
+	}
+
+	mac, err := net.ParseMAC(nameOrMac)
+	if err != nil {
+		return []string{nameOrMac}
+	}
+
+	intfs, err := net.Interfaces()
+	if err != nil {
+		return []string{nameOrMac}
+	}
+
+	for _, intf := range intfs {
+		if bytes.Equal(intf.HardwareAddr, mac) {
+			return interfaceAddresses(network, &intf)
+		}
+	}
+
+	return []string{nameOrMac}
+}
+
+func interfaceAddresses(network string, intf *net.Interface) []string {
+	var out []string
+	addrs, err := intf.Addrs()
+	if err != nil {
+		return out
+	}
+
+	for _, addr := range addrs {
+		ipnet, ok := addr.(*net.IPNet)
+		if ok && (network == "tcp" || (network == "tcp4" && len(ipnet.IP) == net.IPv4len) || (network == "tcp6" && len(ipnet.IP) == net.IPv6len)) {
+			out = append(out, ipnet.IP.String())
+		}
+	}
+
+	return out
+}

lib/osutil/osutil.go

@@ -9,19 +9,16 @@ package osutil
 
 import (
 	"errors"
-	"fmt"
 	"io"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
 
-	"github.com/calmh/du"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/sync"
 )
 
-var errNoHome = errors.New("no home directory found - set $HOME (or the platform equivalent)")
-
 // Try to keep this entire operation atomic-like. We shouldn't be doing this
 // often enough that there is any contention on this lock.
 var renameLock = sync.NewMutex()
@@ -29,12 +26,12 @@ var renameLock = sync.NewMutex()
 // TryRename renames a file, leaving source file intact in case of failure.
 // Tries hard to succeed on various systems by temporarily tweaking directory
 // permissions and removing the destination file when necessary.
-func TryRename(from, to string) error {
+func TryRename(filesystem fs.Filesystem, from, to string) error {
 	renameLock.Lock()
 	defer renameLock.Unlock()
 
-	return withPreparedTarget(from, to, func() error {
-		return os.Rename(from, to)
+	return withPreparedTarget(filesystem, from, to, func() error {
+		return filesystem.Rename(from, to)
 	})
 }
 
@@ -43,28 +40,28 @@ func TryRename(from, to string) error {
 // for situations like committing a temp file to it's final location.
 // Tries hard to succeed on various systems by temporarily tweaking directory
 // permissions and removing the destination file when necessary.
-func Rename(from, to string) error {
+func Rename(filesystem fs.Filesystem, from, to string) error {
 	// Don't leave a dangling temp file in case of rename error
 	if !(runtime.GOOS == "windows" && strings.EqualFold(from, to)) {
-		defer os.Remove(from)
+		defer filesystem.Remove(from)
 	}
-	return TryRename(from, to)
+	return TryRename(filesystem, from, to)
 }
 
 // Copy copies the file content from source to destination.
 // Tries hard to succeed on various systems by temporarily tweaking directory
 // permissions and removing the destination file when necessary.
-func Copy(from, to string) (err error) {
-	return withPreparedTarget(from, to, func() error {
-		return copyFileContents(from, to)
+func Copy(filesystem fs.Filesystem, from, to string) (err error) {
+	return withPreparedTarget(filesystem, from, to, func() error {
+		return copyFileContents(filesystem, from, to)
 	})
 }
 
 // InWritableDir calls fn(path), while making sure that the directory
 // containing `path` is writable for the duration of the call.
-func InWritableDir(fn func(string) error, path string) error {
+func InWritableDir(fn func(string) error, fs fs.Filesystem, path string) error {
 	dir := filepath.Dir(path)
-	info, err := os.Stat(dir)
+	info, err := fs.Stat(dir)
 	if err != nil {
 		return err
 	}
@@ -75,10 +72,10 @@ func InWritableDir(fn func(string) error, path string) error {
 		// A non-writeable directory (for this user; we assume that's the
 		// relevant part). Temporarily change the mode so we can delete the
 		// file or directory inside it.
-		err = os.Chmod(dir, 0755)
+		err = fs.Chmod(dir, 0755)
 		if err == nil {
 			defer func() {
-				err = os.Chmod(dir, info.Mode())
+				err = fs.Chmod(dir, info.Mode())
 				if err != nil {
 					// We managed to change the permission bits like a
 					// millisecond ago, so it'd be bizarre if we couldn't
@@ -92,59 +89,22 @@ func InWritableDir(fn func(string) error, path string) error {
 	return fn(path)
 }
 
-func ExpandTilde(path string) (string, error) {
-	if path == "~" {
-		return getHomeDir()
-	}
-
-	path = filepath.FromSlash(path)
-	if !strings.HasPrefix(path, fmt.Sprintf("~%c", os.PathSeparator)) {
-		return path, nil
-	}
-
-	home, err := getHomeDir()
-	if err != nil {
-		return "", err
-	}
-	return filepath.Join(home, path[2:]), nil
-}
-
-func getHomeDir() (string, error) {
-	var home string
-
-	switch runtime.GOOS {
-	case "windows":
-		home = filepath.Join(os.Getenv("HomeDrive"), os.Getenv("HomePath"))
-		if home == "" {
-			home = os.Getenv("UserProfile")
-		}
-	default:
-		home = os.Getenv("HOME")
-	}
-
-	if home == "" {
-		return "", errNoHome
-	}
-
-	return home, nil
-}
-
 // Tries hard to succeed on various systems by temporarily tweaking directory
 // permissions and removing the destination file when necessary.
-func withPreparedTarget(from, to string, f func() error) error {
+func withPreparedTarget(filesystem fs.Filesystem, from, to string, f func() error) error {
 	// Make sure the destination directory is writeable
 	toDir := filepath.Dir(to)
-	if info, err := os.Stat(toDir); err == nil && info.IsDir() && info.Mode()&0200 == 0 {
-		os.Chmod(toDir, 0755)
-		defer os.Chmod(toDir, info.Mode())
+	if info, err := filesystem.Stat(toDir); err == nil && info.IsDir() && info.Mode()&0200 == 0 {
+		filesystem.Chmod(toDir, 0755)
+		defer filesystem.Chmod(toDir, info.Mode())
 	}
 
 	// On Windows, make sure the destination file is writeable (or we can't delete it)
 	if runtime.GOOS == "windows" {
-		os.Chmod(to, 0666)
+		filesystem.Chmod(to, 0666)
 		if !strings.EqualFold(from, to) {
-			err := os.Remove(to)
-			if err != nil && !os.IsNotExist(err) {
+			err := filesystem.Remove(to)
+			if err != nil && !fs.IsNotExist(err) {
 				return err
 			}
 		}
@@ -156,13 +116,13 @@ func withPreparedTarget(from, to string, f func() error) error {
 // by dst. The file will be created if it does not already exist. If the
 // destination file exists, all it's contents will be replaced by the contents
 // of the source file.
-func copyFileContents(src, dst string) (err error) {
-	in, err := os.Open(src)
+func copyFileContents(filesystem fs.Filesystem, src, dst string) (err error) {
+	in, err := filesystem.Open(src)
 	if err != nil {
 		return
 	}
 	defer in.Close()
-	out, err := os.Create(dst)
+	out, err := filesystem.Create(dst)
 	if err != nil {
 		return
 	}
@@ -193,13 +153,3 @@ func init() {
 func IsWindowsExecutable(path string) bool {
 	return execExts[strings.ToLower(filepath.Ext(path))]
 }
-
-func DiskFreeBytes(path string) (free int64, err error) {
-	u, err := du.Get(path)
-	return u.FreeBytes, err
-}
-
-func DiskFreePercentage(path string) (freePct float64, err error) {
-	u, err := du.Get(path)
-	return (float64(u.FreeBytes) / float64(u.TotalBytes)) * 100, err
-}

lib/osutil/osutil_test.go

@@ -11,6 +11,7 @@ import (
 	"runtime"
 	"testing"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 )
 
@@ -21,6 +22,8 @@ func TestInWriteableDir(t *testing.T) {
 	}
 	defer os.RemoveAll("testdata")
 
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, ".")
+
 	os.Mkdir("testdata", 0700)
 	os.Mkdir("testdata/rw", 0700)
 	os.Mkdir("testdata/ro", 0500)
@@ -36,35 +39,35 @@ func TestInWriteableDir(t *testing.T) {
 
 	// These should succeed
 
-	err = osutil.InWritableDir(create, "testdata/file")
+	err = osutil.InWritableDir(create, fs, "testdata/file")
 	if err != nil {
 		t.Error("testdata/file:", err)
 	}
-	err = osutil.InWritableDir(create, "testdata/rw/foo")
+	err = osutil.InWritableDir(create, fs, "testdata/rw/foo")
 	if err != nil {
 		t.Error("testdata/rw/foo:", err)
 	}
-	err = osutil.InWritableDir(os.Remove, "testdata/rw/foo")
+	err = osutil.InWritableDir(os.Remove, fs, "testdata/rw/foo")
 	if err != nil {
 		t.Error("testdata/rw/foo:", err)
 	}
 
-	err = osutil.InWritableDir(create, "testdata/ro/foo")
+	err = osutil.InWritableDir(create, fs, "testdata/ro/foo")
 	if err != nil {
 		t.Error("testdata/ro/foo:", err)
 	}
-	err = osutil.InWritableDir(os.Remove, "testdata/ro/foo")
+	err = osutil.InWritableDir(os.Remove, fs, "testdata/ro/foo")
 	if err != nil {
 		t.Error("testdata/ro/foo:", err)
 	}
 
 	// These should not
 
-	err = osutil.InWritableDir(create, "testdata/nonexistent/foo")
+	err = osutil.InWritableDir(create, fs, "testdata/nonexistent/foo")
 	if err == nil {
 		t.Error("testdata/nonexistent/foo returned nil error")
 	}
-	err = osutil.InWritableDir(create, "testdata/file/foo")
+	err = osutil.InWritableDir(create, fs, "testdata/file/foo")
 	if err == nil {
 		t.Error("testdata/file/foo returned nil error")
 	}
@@ -101,8 +104,10 @@ func TestInWritableDirWindowsRemove(t *testing.T) {
 	create("testdata/windows/ro/readonly")
 	os.Chmod("testdata/windows/ro/readonly", 0500)
 
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, ".")
+
 	for _, path := range []string{"testdata/windows/ro/readonly", "testdata/windows/ro", "testdata/windows"} {
-		err := osutil.InWritableDir(os.Remove, path)
+		err := osutil.InWritableDir(os.Remove, fs, path)
 		if err != nil {
 			t.Errorf("Unexpected error %s: %s", path, err)
 		}
@@ -174,6 +179,8 @@ func TestInWritableDirWindowsRename(t *testing.T) {
 	create("testdata/windows/ro/readonly")
 	os.Chmod("testdata/windows/ro/readonly", 0500)
 
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, ".")
+
 	for _, path := range []string{"testdata/windows/ro/readonly", "testdata/windows/ro", "testdata/windows"} {
 		err := os.Rename(path, path+"new")
 		if err == nil {
@@ -183,11 +190,11 @@ func TestInWritableDirWindowsRename(t *testing.T) {
 	}
 
 	rename := func(path string) error {
-		return osutil.Rename(path, path+"new")
+		return osutil.Rename(fs, path, path+"new")
 	}
 
 	for _, path := range []string{"testdata/windows/ro/readonly", "testdata/windows/ro", "testdata/windows"} {
-		err := osutil.InWritableDir(rename, path)
+		err := osutil.InWritableDir(rename, fs, path)
 		if err != nil {
 			t.Errorf("Unexpected error %s: %s", path, err)
 		}
@@ -197,18 +204,3 @@ func TestInWritableDirWindowsRename(t *testing.T) {
 		}
 	}
 }
-
-func TestDiskUsage(t *testing.T) {
-	free, err := osutil.DiskFreePercentage(".")
-	if err != nil {
-		if runtime.GOOS == "netbsd" ||
-			runtime.GOOS == "openbsd" ||
-			runtime.GOOS == "solaris" {
-			t.Skip()
-		}
-		t.Errorf("Unexpected error: %s", err)
-	}
-	if free < 1 {
-		t.Error("Disk is full?", free)
-	}
-}

lib/osutil/sync.go

@@ -1,34 +0,0 @@
-// Copyright (C) 2016 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-package osutil
-
-import (
-	"os"
-	"runtime"
-)
-
-func SyncFile(path string) error {
-	flag := 0
-	if runtime.GOOS == "windows" {
-		flag = os.O_WRONLY
-	}
-	fd, err := os.OpenFile(path, flag, 0)
-	if err != nil {
-		return err
-	}
-	defer fd.Close()
-	// MacOS and Windows do not flush the disk cache
-	return fd.Sync()
-}
-
-func SyncDir(path string) error {
-	if runtime.GOOS == "windows" {
-		// not supported by Windows
-		return nil
-	}
-	return SyncFile(path)
-}

lib/osutil/tempfile.go

@@ -0,0 +1,63 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package osutil
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/syncthing/syncthing/lib/fs"
+)
+
+var rand uint32
+var randmu sync.Mutex
+
+func reseed() uint32 {
+	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
+}
+
+func nextSuffix() string {
+	randmu.Lock()
+	r := rand
+	if r == 0 {
+		r = reseed()
+	}
+	r = r*1664525 + 1013904223 // constants from Numerical Recipes
+	rand = r
+	randmu.Unlock()
+	return strconv.Itoa(int(1e9 + r%1e9))[1:]
+}
+
+// TempFile creates a new temporary file in the directory dir
+// with a name beginning with prefix, opens the file for reading
+// and writing, and returns the resulting *os.File.
+// If dir is the empty string, TempFile uses the default directory
+// for temporary files (see os.TempDir).
+// Multiple programs calling TempFile simultaneously
+// will not choose the same file. The caller can use f.Name()
+// to find the pathname of the file. It is the caller's responsibility
+// to remove the file when no longer needed.
+func TempFile(filesystem fs.Filesystem, dir, prefix string) (f fs.File, err error) {
+	nconflict := 0
+	for i := 0; i < 10000; i++ {
+		name := filepath.Join(dir, prefix+nextSuffix())
+		f, err = filesystem.OpenFile(name, fs.OptReadWrite|fs.OptCreate|fs.OptExclusive, 0600)
+		if fs.IsExist(err) {
+			if nconflict++; nconflict > 10 {
+				randmu.Lock()
+				rand = reseed()
+				randmu.Unlock()
+			}
+			continue
+		}
+		break
+	}
+	return
+}

lib/osutil/traversessymlink.go

@@ -8,9 +8,10 @@ package osutil
 
 import (
 	"fmt"
-	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 // TraversesSymlinkError is an error indicating symlink traversal
@@ -34,9 +35,10 @@ func (e NotADirectoryError) Error() string {
 // TraversesSymlink returns an error if base and any path component of name up to and
 // including filepath.Join(base, name) traverses a symlink.
 // Base and name must both be clean and name must be relative to base.
-func TraversesSymlink(base, name string) error {
+func TraversesSymlink(filesystem fs.Filesystem, name string) error {
+	base := "."
 	path := base
-	info, err := Lstat(path)
+	info, err := filesystem.Lstat(path)
 	if err != nil {
 		return err
 	}
@@ -51,17 +53,17 @@ func TraversesSymlink(base, name string) error {
 		return nil
 	}
 
-	parts := strings.Split(name, string(os.PathSeparator))
+	parts := strings.Split(name, string(fs.PathSeparator))
 	for _, part := range parts {
 		path = filepath.Join(path, part)
-		info, err := Lstat(path)
+		info, err := filesystem.Lstat(path)
 		if err != nil {
-			if os.IsNotExist(err) {
+			if fs.IsNotExist(err) {
 				return nil
 			}
 			return err
 		}
-		if info.Mode()&os.ModeSymlink != 0 {
+		if info.IsSymlink() {
 			return &TraversesSymlinkError{
 				path: strings.TrimPrefix(path, base),
 			}

lib/osutil/traversessymlink_test.go

@@ -12,17 +12,20 @@ import (
 	"os"
 	"testing"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 )
 
 func TestTraversesSymlink(t *testing.T) {
 	os.RemoveAll("testdata")
 	defer os.RemoveAll("testdata")
-	os.MkdirAll("testdata/a/b/c", 0755)
-	os.Symlink("b", "testdata/a/l")
+
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata")
+	fs.MkdirAll("a/b/c", 0755)
+	fs.CreateSymlink("b", "a/l")
 
 	// a/l -> b, so a/l/c should resolve by normal stat
-	info, err := osutil.Lstat("testdata/a/l/c")
+	info, err := fs.Lstat("a/l/c")
 	if err != nil {
 		t.Fatal("unexpected error", err)
 	}
@@ -52,7 +55,7 @@ func TestTraversesSymlink(t *testing.T) {
 	}
 
 	for _, tc := range cases {
-		if res := osutil.TraversesSymlink("testdata", tc.name); tc.traverses == (res == nil) {
+		if res := osutil.TraversesSymlink(fs, tc.name); tc.traverses == (res == nil) {
 			t.Errorf("TraversesSymlink(%q) = %v, should be %v", tc.name, res, tc.traverses)
 		}
 	}
@@ -63,10 +66,11 @@ var traversesSymlinkResult error
 func BenchmarkTraversesSymlink(b *testing.B) {
 	os.RemoveAll("testdata")
 	defer os.RemoveAll("testdata")
-	os.MkdirAll("testdata/a/b/c", 0755)
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata")
+	fs.MkdirAll("a/b/c", 0755)
 
 	for i := 0; i < b.N; i++ {
-		traversesSymlinkResult = osutil.TraversesSymlink("testdata", "a/b/c")
+		traversesSymlinkResult = osutil.TraversesSymlink(fs, "a/b/c")
 	}
 
 	b.ReportAllocs()

lib/scanner/blockqueue.go

@@ -9,7 +9,6 @@ package scanner
 import (
 	"context"
 	"errors"
-	"path/filepath"
 
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
@@ -64,7 +63,6 @@ func HashFile(ctx context.Context, fs fs.Filesystem, path string, blockSize int,
 // is closed and all items handled.
 type parallelHasher struct {
 	fs            fs.Filesystem
-	dir           string
 	blockSize     int
 	workers       int
 	outbox        chan<- protocol.FileInfo
@@ -75,10 +73,9 @@ type parallelHasher struct {
 	wg            sync.WaitGroup
 }
 
-func newParallelHasher(ctx context.Context, fs fs.Filesystem, dir string, blockSize, workers int, outbox chan<- protocol.FileInfo, inbox <-chan protocol.FileInfo, counter Counter, done chan<- struct{}, useWeakHashes bool) {
+func newParallelHasher(ctx context.Context, fs fs.Filesystem, blockSize, workers int, outbox chan<- protocol.FileInfo, inbox <-chan protocol.FileInfo, counter Counter, done chan<- struct{}, useWeakHashes bool) {
 	ph := &parallelHasher{
 		fs:            fs,
-		dir:           dir,
 		blockSize:     blockSize,
 		workers:       workers,
 		outbox:        outbox,
@@ -111,7 +108,7 @@ func (ph *parallelHasher) hashFiles(ctx context.Context) {
 				panic("Bug. Asked to hash a directory or a deleted file.")
 			}
 
-			blocks, err := HashFile(ctx, ph.fs, filepath.Join(ph.dir, f.Name), ph.blockSize, ph.counter, ph.useWeakHashes)
+			blocks, err := HashFile(ctx, ph.fs, f.Name, ph.blockSize, ph.counter, ph.useWeakHashes)
 			if err != nil {
 				l.Debugln("hash error:", f.Name, err)
 				continue

lib/scanner/infinitefs_test.go

@@ -19,6 +19,7 @@ import (
 )
 
 type infiniteFS struct {
+	fs.Filesystem
 	width    int   // number of files and directories per level
 	depth    int   // number of tree levels to simulate
 	filesize int64 // size of each file in bytes
@@ -50,18 +51,6 @@ func (i infiniteFS) Open(name string) (fs.File, error) {
 	return &fakeFile{name, i.filesize, 0}, nil
 }
 
-func (infiniteFS) Chmod(name string, mode fs.FileMode) error                   { return errNotSupp }
-func (infiniteFS) Chtimes(name string, atime time.Time, mtime time.Time) error { return errNotSupp }
-func (infiniteFS) Create(name string) (fs.File, error)                         { return nil, errNotSupp }
-func (infiniteFS) CreateSymlink(name, target string) error                     { return errNotSupp }
-func (infiniteFS) Mkdir(name string, perm fs.FileMode) error                   { return errNotSupp }
-func (infiniteFS) ReadSymlink(name string) (string, error)                     { return "", errNotSupp }
-func (infiniteFS) Remove(name string) error                                    { return errNotSupp }
-func (infiniteFS) Rename(oldname, newname string) error                        { return errNotSupp }
-func (infiniteFS) Stat(name string) (fs.FileInfo, error)                       { return nil, errNotSupp }
-func (infiniteFS) SymlinksSupported() bool                                     { return false }
-func (infiniteFS) Walk(root string, walkFn fs.WalkFunc) error                  { return errNotSupp }
-
 type fakeInfo struct {
 	name string
 	size int64
@@ -71,7 +60,7 @@ func (f fakeInfo) Name() string       { return f.name }
 func (f fakeInfo) Mode() fs.FileMode  { return 0755 }
 func (f fakeInfo) Size() int64        { return f.size }
 func (f fakeInfo) ModTime() time.Time { return time.Unix(1234567890, 0) }
-func (f fakeInfo) IsDir() bool        { return strings.Contains(filepath.Base(f.name), "dir") }
+func (f fakeInfo) IsDir() bool        { return strings.Contains(filepath.Base(f.name), "dir") || f.name == "." }
 func (f fakeInfo) IsRegular() bool    { return !f.IsDir() }
 func (f fakeInfo) IsSymlink() bool    { return false }
 
@@ -81,6 +70,10 @@ type fakeFile struct {
 	readOffset int64
 }
 
+func (f *fakeFile) Name() string {
+	return f.name
+}
+
 func (f *fakeFile) Read(bs []byte) (int, error) {
 	remaining := f.size - f.readOffset
 	if remaining == 0 {
@@ -98,6 +91,10 @@ func (f *fakeFile) Stat() (fs.FileInfo, error) {
 	return fakeInfo{f.name, f.size}, nil
 }
 
-func (f *fakeFile) WriteAt(bs []byte, offs int64) (int, error) { return 0, errNotSupp }
-func (f *fakeFile) Close() error                               { return nil }
-func (f *fakeFile) Truncate(size int64) error                  { return errNotSupp }
+func (f *fakeFile) Write([]byte) (int, error)          { return 0, errNotSupp }
+func (f *fakeFile) WriteAt([]byte, int64) (int, error) { return 0, errNotSupp }
+func (f *fakeFile) Close() error                       { return nil }
+func (f *fakeFile) Truncate(size int64) error          { return errNotSupp }
+func (f *fakeFile) ReadAt([]byte, int64) (int, error)  { return 0, errNotSupp }
+func (f *fakeFile) Seek(int64, int) (int64, error)     { return 0, errNotSupp }
+func (f *fakeFile) Sync() error                        { return nil }

lib/scanner/walk.go

@@ -9,7 +9,6 @@ package scanner
 import (
 	"context"
 	"errors"
-	"path/filepath"
 	"runtime"
 	"sync/atomic"
 	"time"
@@ -42,8 +41,6 @@ func init() {
 type Config struct {
 	// Folder for which the walker has been created
 	Folder string
-	// Dir is the base directory for the walk
-	Dir string
 	// Limit walking to these paths within Dir, or no limit if Sub is empty
 	Subs []string
 	// BlockSize controls the size of the block used when hashing.
@@ -86,7 +83,7 @@ func Walk(ctx context.Context, cfg Config) (chan protocol.FileInfo, error) {
 		w.CurrentFiler = noCurrentFiler{}
 	}
 	if w.Filesystem == nil {
-		w.Filesystem = fs.DefaultFilesystem
+		panic("no filesystem specified")
 	}
 
 	return w.walk(ctx)
@@ -99,7 +96,7 @@ type walker struct {
 // Walk returns the list of files found in the local folder by scanning the
 // file system. Files are blockwise hashed.
 func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
-	l.Debugln("Walk", w.Dir, w.Subs, w.BlockSize, w.Matcher)
+	l.Debugln("Walk", w.Subs, w.BlockSize, w.Matcher)
 
 	if err := w.checkDir(); err != nil {
 		return nil, err
@@ -113,10 +110,10 @@ func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
 	go func() {
 		hashFiles := w.walkAndHashFiles(ctx, toHashChan, finishedChan)
 		if len(w.Subs) == 0 {
-			w.Filesystem.Walk(w.Dir, hashFiles)
+			w.Filesystem.Walk(".", hashFiles)
 		} else {
 			for _, sub := range w.Subs {
-				w.Filesystem.Walk(filepath.Join(w.Dir, sub), hashFiles)
+				w.Filesystem.Walk(sub, hashFiles)
 			}
 		}
 		close(toHashChan)
@@ -125,7 +122,7 @@ func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
 	// We're not required to emit scan progress events, just kick off hashers,
 	// and feed inputs directly from the walker.
 	if w.ProgressTickIntervalS < 0 {
-		newParallelHasher(ctx, w.Filesystem, w.Dir, w.BlockSize, w.Hashers, finishedChan, toHashChan, nil, nil, w.UseWeakHashes)
+		newParallelHasher(ctx, w.Filesystem, w.BlockSize, w.Hashers, finishedChan, toHashChan, nil, nil, w.UseWeakHashes)
 		return finishedChan, nil
 	}
 
@@ -156,7 +153,7 @@ func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
 		done := make(chan struct{})
 		progress := newByteCounter()
 
-		newParallelHasher(ctx, w.Filesystem, w.Dir, w.BlockSize, w.Hashers, finishedChan, realToHashChan, progress, done, w.UseWeakHashes)
+		newParallelHasher(ctx, w.Filesystem, w.BlockSize, w.Hashers, finishedChan, realToHashChan, progress, done, w.UseWeakHashes)
 
 		// A routine which actually emits the FolderScanProgress events
 		// every w.ProgressTicker ticks, until the hasher routines terminate.
@@ -166,13 +163,13 @@ func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
 			for {
 				select {
 				case <-done:
-					l.Debugln("Walk progress done", w.Dir, w.Subs, w.BlockSize, w.Matcher)
+					l.Debugln("Walk progress done", w.Folder, w.Subs, w.BlockSize, w.Matcher)
 					ticker.Stop()
 					return
 				case <-ticker.C:
 					current := progress.Total()
 					rate := progress.Rate()
-					l.Debugf("Walk %s %s current progress %d/%d at %.01f MiB/s (%d%%)", w.Dir, w.Subs, current, total, rate/1024/1024, current*100/total)
+					l.Debugf("Walk %s %s current progress %d/%d at %.01f MiB/s (%d%%)", w.Folder, w.Subs, current, total, rate/1024/1024, current*100/total)
 					events.Default.Log(events.FolderScanProgress, map[string]interface{}{
 						"folder":  w.Folder,
 						"current": current,
@@ -203,7 +200,7 @@ func (w *walker) walk(ctx context.Context) (chan protocol.FileInfo, error) {
 
 func (w *walker) walkAndHashFiles(ctx context.Context, fchan, dchan chan protocol.FileInfo) fs.WalkFunc {
 	now := time.Now()
-	return func(absPath string, info fs.FileInfo, err error) error {
+	return func(path string, info fs.FileInfo, err error) error {
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
@@ -219,58 +216,52 @@ func (w *walker) walkAndHashFiles(ctx context.Context, fchan, dchan chan protoco
 		}
 
 		if err != nil {
-			l.Debugln("error:", absPath, info, err)
+			l.Debugln("error:", path, info, err)
 			return skip
 		}
 
-		relPath, err := filepath.Rel(w.Dir, absPath)
-		if err != nil {
-			l.Debugln("rel error:", absPath, err)
-			return skip
-		}
-
-		if relPath == "." {
+		if path == "." {
 			return nil
 		}
 
-		info, err = w.Filesystem.Lstat(absPath)
+		info, err = w.Filesystem.Lstat(path)
 		// An error here would be weird as we've already gotten to this point, but act on it nonetheless
 		if err != nil {
 			return skip
 		}
 
-		if ignore.IsTemporary(relPath) {
-			l.Debugln("temporary:", relPath)
+		if ignore.IsTemporary(path) {
+			l.Debugln("temporary:", path)
 			if info.IsRegular() && info.ModTime().Add(w.TempLifetime).Before(now) {
-				w.Filesystem.Remove(absPath)
-				l.Debugln("removing temporary:", relPath, info.ModTime())
+				w.Filesystem.Remove(path)
+				l.Debugln("removing temporary:", path, info.ModTime())
 			}
 			return nil
 		}
 
-		if ignore.IsInternal(relPath) {
-			l.Debugln("ignored (internal):", relPath)
+		if ignore.IsInternal(path) {
+			l.Debugln("ignored (internal):", path)
 			return skip
 		}
 
-		if w.Matcher.Match(relPath).IsIgnored() {
-			l.Debugln("ignored (patterns):", relPath)
+		if w.Matcher.Match(path).IsIgnored() {
+			l.Debugln("ignored (patterns):", path)
 			return skip
 		}
 
-		if !utf8.ValidString(relPath) {
-			l.Warnf("File name %q is not in UTF8 encoding; skipping.", relPath)
+		if !utf8.ValidString(path) {
+			l.Warnf("File name %q is not in UTF8 encoding; skipping.", path)
 			return skip
 		}
 
-		relPath, shouldSkip := w.normalizePath(absPath, relPath)
+		path, shouldSkip := w.normalizePath(path)
 		if shouldSkip {
 			return skip
 		}
 
 		switch {
 		case info.IsSymlink():
-			if err := w.walkSymlink(ctx, absPath, relPath, dchan); err != nil {
+			if err := w.walkSymlink(ctx, path, dchan); err != nil {
 				return err
 			}
 			if info.IsDir() {
@@ -280,10 +271,10 @@ func (w *walker) walkAndHashFiles(ctx context.Context, fchan, dchan chan protoco
 			return nil
 
 		case info.IsDir():
-			err = w.walkDir(ctx, relPath, info, dchan)
+			err = w.walkDir(ctx, path, info, dchan)
 
 		case info.IsRegular():
-			err = w.walkRegular(ctx, relPath, info, fchan)
+			err = w.walkRegular(ctx, path, info, fchan)
 		}
 
 		return err
@@ -375,7 +366,7 @@ func (w *walker) walkDir(ctx context.Context, relPath string, info fs.FileInfo,
 
 // walkSymlink returns nil or an error, if the error is of the nature that
 // it should stop the entire walk.
-func (w *walker) walkSymlink(ctx context.Context, absPath, relPath string, dchan chan protocol.FileInfo) error {
+func (w *walker) walkSymlink(ctx context.Context, relPath string, dchan chan protocol.FileInfo) error {
 	// Symlinks are not supported on Windows. We ignore instead of returning
 	// an error.
 	if runtime.GOOS == "windows" {
@@ -387,9 +378,9 @@ func (w *walker) walkSymlink(ctx context.Context, absPath, relPath string, dchan
 	// checking that their existing blocks match with the blocks in
 	// the index.
 
-	target, err := w.Filesystem.ReadSymlink(absPath)
+	target, err := w.Filesystem.ReadSymlink(relPath)
 	if err != nil {
-		l.Debugln("readlink error:", absPath, err)
+		l.Debugln("readlink error:", relPath, err)
 		return nil
 	}
 
@@ -413,7 +404,7 @@ func (w *walker) walkSymlink(ctx context.Context, absPath, relPath string, dchan
 		SymlinkTarget: target,
 	}
 
-	l.Debugln("symlink changedb:", absPath, f)
+	l.Debugln("symlink changedb:", relPath, f)
 
 	select {
 	case dchan <- f:
@@ -426,55 +417,58 @@ func (w *walker) walkSymlink(ctx context.Context, absPath, relPath string, dchan
 
 // normalizePath returns the normalized relative path (possibly after fixing
 // it on disk), or skip is true.
-func (w *walker) normalizePath(absPath, relPath string) (normPath string, skip bool) {
+func (w *walker) normalizePath(path string) (normPath string, skip bool) {
 	if runtime.GOOS == "darwin" {
 		// Mac OS X file names should always be NFD normalized.
-		normPath = norm.NFD.String(relPath)
+		normPath = norm.NFD.String(path)
 	} else {
 		// Every other OS in the known universe uses NFC or just plain
 		// doesn't bother to define an encoding. In our case *we* do care,
 		// so we enforce NFC regardless.
-		normPath = norm.NFC.String(relPath)
+		normPath = norm.NFC.String(path)
 	}
 
-	if relPath != normPath {
+	if path != normPath {
 		// The file name was not normalized.
 
 		if !w.AutoNormalize {
 			// We're not authorized to do anything about it, so complain and skip.
 
-			l.Warnf("File name %q is not in the correct UTF8 normalization form; skipping.", relPath)
+			l.Warnf("File name %q is not in the correct UTF8 normalization form; skipping.", path)
 			return "", true
 		}
 
 		// We will attempt to normalize it.
-		normalizedPath := filepath.Join(w.Dir, normPath)
-		if _, err := w.Filesystem.Lstat(normalizedPath); fs.IsNotExist(err) {
+		if _, err := w.Filesystem.Lstat(normPath); fs.IsNotExist(err) {
 			// Nothing exists with the normalized filename. Good.
-			if err = w.Filesystem.Rename(absPath, normalizedPath); err != nil {
-				l.Infof(`Error normalizing UTF8 encoding of file "%s": %v`, relPath, err)
+			if err = w.Filesystem.Rename(path, normPath); err != nil {
+				l.Infof(`Error normalizing UTF8 encoding of file "%s": %v`, path, err)
 				return "", true
 			}
-			l.Infof(`Normalized UTF8 encoding of file name "%s".`, relPath)
+			l.Infof(`Normalized UTF8 encoding of file name "%s".`, path)
 		} else {
 			// There is something already in the way at the normalized
 			// file name.
-			l.Infof(`File "%s" has UTF8 encoding conflict with another file; ignoring.`, relPath)
+			l.Infof(`File "%s" path has UTF8 encoding conflict with another file; ignoring.`, path)
 			return "", true
 		}
 	}
 
-	return normPath, false
+	return path, false
 }
 
 func (w *walker) checkDir() error {
-	if info, err := w.Filesystem.Lstat(w.Dir); err != nil {
+	info, err := w.Filesystem.Lstat(".")
+	if err != nil {
 		return err
-	} else if !info.IsDir() {
-		return errors.New(w.Dir + ": not a directory")
-	} else {
-		l.Debugln("checkDir", w.Dir, info)
 	}
+
+	if !info.IsDir() {
+		return errors.New(w.Filesystem.URI() + ": not a directory")
+	}
+
+	l.Debugln("checkDir", w.Filesystem.Type(), w.Filesystem.URI(), info)
+
 	return nil
 }
 

lib/scanner/walk_test.go

@@ -23,7 +23,6 @@ import (
 	"github.com/d4l3k/messagediff"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/ignore"
-	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"golang.org/x/text/unicode/norm"
 )
@@ -54,18 +53,18 @@ func init() {
 }
 
 func TestWalkSub(t *testing.T) {
-	ignores := ignore.New()
+	ignores := ignore.New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."))
 	err := ignores.Load("testdata/.stignore")
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	fchan, err := Walk(context.TODO(), Config{
-		Dir:       "testdata",
-		Subs:      []string{"dir2"},
-		BlockSize: 128 * 1024,
-		Matcher:   ignores,
-		Hashers:   2,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
+		Subs:       []string{"dir2"},
+		BlockSize:  128 * 1024,
+		Matcher:    ignores,
+		Hashers:    2,
 	})
 	var files []protocol.FileInfo
 	for f := range fchan {
@@ -90,7 +89,7 @@ func TestWalkSub(t *testing.T) {
 }
 
 func TestWalk(t *testing.T) {
-	ignores := ignore.New()
+	ignores := ignore.New(fs.NewFilesystem(fs.FilesystemTypeBasic, "."))
 	err := ignores.Load("testdata/.stignore")
 	if err != nil {
 		t.Fatal(err)
@@ -98,10 +97,10 @@ func TestWalk(t *testing.T) {
 	t.Log(ignores)
 
 	fchan, err := Walk(context.TODO(), Config{
-		Dir:       "testdata",
-		BlockSize: 128 * 1024,
-		Matcher:   ignores,
-		Hashers:   2,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"),
+		BlockSize:  128 * 1024,
+		Matcher:    ignores,
+		Hashers:    2,
 	})
 
 	if err != nil {
@@ -122,9 +121,9 @@ func TestWalk(t *testing.T) {
 
 func TestWalkError(t *testing.T) {
 	_, err := Walk(context.TODO(), Config{
-		Dir:       "testdata-missing",
-		BlockSize: 128 * 1024,
-		Hashers:   2,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata-missing"),
+		BlockSize:  128 * 1024,
+		Hashers:    2,
 	})
 
 	if err == nil {
@@ -132,8 +131,8 @@ func TestWalkError(t *testing.T) {
 	}
 
 	_, err = Walk(context.TODO(), Config{
-		Dir:       "testdata/bar",
-		BlockSize: 128 * 1024,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata/bar"),
+		BlockSize:  128 * 1024,
 	})
 
 	if err == nil {
@@ -220,9 +219,11 @@ func TestNormalization(t *testing.T) {
 
 	numValid := len(tests) - numInvalid
 
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, ".")
+
 	for _, s1 := range tests {
 		// Create a directory for each of the interesting strings above
-		if err := osutil.MkdirAll(filepath.Join("testdata/normalization", s1), 0755); err != nil {
+		if err := fs.MkdirAll(filepath.Join("testdata/normalization", s1), 0755); err != nil {
 			t.Fatal(err)
 		}
 
@@ -231,10 +232,10 @@ func TestNormalization(t *testing.T) {
 			// file names. Ensure that the file doesn't exist when it's
 			// created. This detects and fails if there's file name
 			// normalization stuff at the filesystem level.
-			if fd, err := os.OpenFile(filepath.Join("testdata/normalization", s1, s2), os.O_CREATE|os.O_EXCL, 0644); err != nil {
+			if fd, err := fs.OpenFile(filepath.Join("testdata/normalization", s1, s2), os.O_CREATE|os.O_EXCL, 0644); err != nil {
 				t.Fatal(err)
 			} else {
-				fd.WriteString("test")
+				fd.Write([]byte("test"))
 				fd.Close()
 			}
 		}
@@ -245,11 +246,11 @@ func TestNormalization(t *testing.T) {
 	// make sure it all gets done. In production, things will be correct
 	// eventually...
 
-	_, err := walkDir("testdata/normalization")
+	_, err := walkDir(fs, "testdata/normalization")
 	if err != nil {
 		t.Fatal(err)
 	}
-	tmp, err := walkDir("testdata/normalization")
+	tmp, err := walkDir(fs, "testdata/normalization")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -299,8 +300,8 @@ func TestWalkSymlinkUnix(t *testing.T) {
 	// Scan it
 
 	fchan, err := Walk(context.TODO(), Config{
-		Dir:       "_symlinks",
-		BlockSize: 128 * 1024,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "_symlinks"),
+		BlockSize:  128 * 1024,
 	})
 
 	if err != nil {
@@ -344,8 +345,8 @@ func TestWalkSymlinkWindows(t *testing.T) {
 	// Scan it
 
 	fchan, err := Walk(context.TODO(), Config{
-		Dir:       "_symlinks",
-		BlockSize: 128 * 1024,
+		Filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "_symlinks"),
+		BlockSize:  128 * 1024,
 	})
 
 	if err != nil {
@@ -364,9 +365,10 @@ func TestWalkSymlinkWindows(t *testing.T) {
 	}
 }
 
-func walkDir(dir string) ([]protocol.FileInfo, error) {
+func walkDir(fs fs.Filesystem, dir string) ([]protocol.FileInfo, error) {
 	fchan, err := Walk(context.TODO(), Config{
-		Dir:           dir,
+		Filesystem:    fs,
+		Subs:          []string{dir},
 		BlockSize:     128 * 1024,
 		AutoNormalize: true,
 		Hashers:       2,
@@ -435,7 +437,7 @@ func BenchmarkHashFile(b *testing.B) {
 	b.ResetTimer()
 
 	for i := 0; i < b.N; i++ {
-		if _, err := HashFile(context.TODO(), fs.DefaultFilesystem, testdataName, protocol.BlockSize, nil, true); err != nil {
+		if _, err := HashFile(context.TODO(), fs.NewFilesystem(fs.FilesystemTypeBasic, ""), testdataName, protocol.BlockSize, nil, true); err != nil {
 			b.Fatal(err)
 		}
 	}
@@ -467,15 +469,17 @@ func TestStopWalk(t *testing.T) {
 	// many directories. It'll take a while to scan, giving us time to
 	// cancel it and make sure the scan stops.
 
-	fs := fs.NewWalkFilesystem(&infiniteFS{100, 100, 1e6})
+	// Use an errorFs as the backing fs for the rest of the interface
+	// The way we get it is a bit hacky tho.
+	errorFs := fs.NewFilesystem(fs.FilesystemType(-1), ".")
+	fs := fs.NewWalkFilesystem(&infiniteFS{errorFs, 100, 100, 1e6})
 
 	const numHashers = 4
 	ctx, cancel := context.WithCancel(context.Background())
 	fchan, err := Walk(ctx, Config{
-		Dir:                   "testdir",
+		Filesystem:            fs,
 		BlockSize:             128 * 1024,
 		Hashers:               numHashers,
-		Filesystem:            fs,
 		ProgressTickIntervalS: -1, // Don't attempt to build the full list of files before starting to scan...
 	})
 

lib/upnp/upnp.go

@@ -42,7 +42,6 @@ import (
 	"net"
 	"net/http"
 	"net/url"
-	"regexp"
 	"runtime"
 	"strings"
 	"time"
@@ -168,7 +167,9 @@ USER-AGENT: syncthing/1.0
 
 	_, err = socket.WriteTo(search, ssdp)
 	if err != nil {
-		l.Infoln(err)
+		if e, ok := err.(net.Error); !ok || !e.Timeout() {
+			l.Infoln(err)
+		}
 		return
 	}
 
@@ -226,11 +227,6 @@ func parseResponse(deviceType string, resp []byte) (IGD, error) {
 	}
 
 	deviceUUID := strings.TrimPrefix(strings.Split(deviceUSN, "::")[0], "uuid:")
-	matched, _ := regexp.MatchString("[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}", deviceUUID)
-	if !matched {
-		l.Infoln("Invalid IGD response: invalid device UUID", deviceUUID, "(continuing anyway)")
-	}
-
 	response, err = http.Get(deviceDescriptionLocation)
 	if err != nil {
 		return IGD{}, err

lib/versioner/external.go

@@ -10,10 +10,11 @@ import (
 	"errors"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"strings"
 
-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
+
+	"github.com/kballard/go-shellquote"
 )
 
 func init() {
@@ -23,15 +24,15 @@ func init() {
 
 type External struct {
 	command    string
-	folderPath string
+	filesystem fs.Filesystem
 }
 
-func NewExternal(folderID, folderPath string, params map[string]string) Versioner {
+func NewExternal(folderID string, filesystem fs.Filesystem, params map[string]string) Versioner {
 	command := params["command"]
 
 	s := External{
 		command:    command,
-		folderPath: folderPath,
+		filesystem: filesystem,
 	}
 
 	l.Debugf("instantiated %#v", s)
@@ -41,26 +42,41 @@ func NewExternal(folderID, folderPath string, params map[string]string) Versione
 // Archive moves the named file away to a version archive. If this function
 // returns nil, the named file does not exist any more (has been archived).
 func (v External) Archive(filePath string) error {
-	_, err := osutil.Lstat(filePath)
-	if os.IsNotExist(err) {
+	info, err := v.filesystem.Lstat(filePath)
+	if fs.IsNotExist(err) {
 		l.Debugln("not archiving nonexistent file", filePath)
 		return nil
 	} else if err != nil {
 		return err
 	}
+	if info.IsSymlink() {
+		panic("bug: attempting to version a symlink")
+	}
 
 	l.Debugln("archiving", filePath)
 
-	inFolderPath, err := filepath.Rel(v.folderPath, filePath)
-	if err != nil {
-		return err
-	}
-
 	if v.command == "" {
 		return errors.New("Versioner: command is empty, please enter a valid command")
 	}
 
-	cmd := exec.Command(v.command, v.folderPath, inFolderPath)
+	words, err := shellquote.Split(v.command)
+	if err != nil {
+		return errors.New("Versioner: command is invalid: " + err.Error())
+	}
+
+	context := map[string]string{
+		"%FOLDER_FILESYSTEM%": v.filesystem.Type().String(),
+		"%FOLDER_PATH%":       v.filesystem.URI(),
+		"%FILE_PATH%":         filePath,
+	}
+
+	for i, word := range words {
+		if replacement, ok := context[word]; ok {
+			words[i] = replacement
+		}
+	}
+
+	cmd := exec.Command(words[0], words[1:]...)
 	env := os.Environ()
 	// filter STGUIAUTH and STGUIAPIKEY from environment variables
 	filteredEnv := []string{}
@@ -70,13 +86,14 @@ func (v External) Archive(filePath string) error {
 		}
 	}
 	cmd.Env = filteredEnv
-	err = cmd.Run()
+	combinedOutput, err := cmd.CombinedOutput()
+	l.Debugln("external command output:", string(combinedOutput))
 	if err != nil {
 		return err
 	}
 
 	// return error if the file was not removed
-	if _, err = osutil.Lstat(filePath); os.IsNotExist(err) {
+	if _, err = v.filesystem.Lstat(filePath); fs.IsNotExist(err) {
 		return nil
 	}
 	return errors.New("Versioner: file was not removed by external script")

lib/versioner/external_test.go

@@ -12,6 +12,8 @@ import (
 	"path/filepath"
 	"runtime"
 	"testing"
+
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func TestExternalNoCommand(t *testing.T) {
@@ -28,8 +30,8 @@ func TestExternalNoCommand(t *testing.T) {
 	// The versioner should fail due to missing command.
 
 	e := External{
+		filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "."),
 		command:    "nonexistent command",
-		folderPath: "testdata/folder path",
 	}
 	if err := e.Archive(file); err == nil {
 		t.Error("Command should have failed")
@@ -43,12 +45,12 @@ func TestExternalNoCommand(t *testing.T) {
 }
 
 func TestExternal(t *testing.T) {
-	cmd := "./_external_test/external.sh"
+	cmd := "./_external_test/external.sh %FOLDER_PATH% %FILE_PATH%"
 	if runtime.GOOS == "windows" {
-		cmd = `.\_external_test\external.bat`
+		cmd = `.\\_external_test\\external.bat %FOLDER_PATH% %FILE_PATH%`
 	}
 
-	file := "testdata/folder path/dir (parens)/long filename (parens).txt"
+	file := filepath.Join("testdata", "folder path", "dir (parens)", "/long filename (parens).txt")
 	prepForRemoval(t, file)
 	defer os.RemoveAll("testdata")
 
@@ -61,8 +63,8 @@ func TestExternal(t *testing.T) {
 	// The versioner should run successfully.
 
 	e := External{
+		filesystem: fs.NewFilesystem(fs.FilesystemTypeBasic, "."),
 		command:    cmd,
-		folderPath: "testdata/folder path",
 	}
 	if err := e.Archive(file); err != nil {
 		t.Fatal(err)

lib/versioner/simple.go

@@ -7,10 +7,10 @@
 package versioner
 
 import (
-	"os"
 	"path/filepath"
 	"strconv"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/util"
 )
@@ -21,19 +21,19 @@ func init() {
 }
 
 type Simple struct {
-	keep       int
-	folderPath string
+	keep int
+	fs   fs.Filesystem
 }
 
-func NewSimple(folderID, folderPath string, params map[string]string) Versioner {
+func NewSimple(folderID string, fs fs.Filesystem, params map[string]string) Versioner {
 	keep, err := strconv.Atoi(params["keep"])
 	if err != nil {
 		keep = 5 // A reasonable default
 	}
 
 	s := Simple{
-		keep:       keep,
-		folderPath: folderPath,
+		keep: keep,
+		fs:   fs,
 	}
 
 	l.Debugf("instantiated %#v", s)
@@ -43,21 +43,24 @@ func NewSimple(folderID, folderPath string, params map[string]string) Versioner
 // Archive moves the named file away to a version archive. If this function
 // returns nil, the named file does not exist any more (has been archived).
 func (v Simple) Archive(filePath string) error {
-	fileInfo, err := osutil.Lstat(filePath)
-	if os.IsNotExist(err) {
+	info, err := v.fs.Lstat(filePath)
+	if fs.IsNotExist(err) {
 		l.Debugln("not archiving nonexistent file", filePath)
 		return nil
 	} else if err != nil {
 		return err
 	}
+	if info.IsSymlink() {
+		panic("bug: attempting to version a symlink")
+	}
 
-	versionsDir := filepath.Join(v.folderPath, ".stversions")
-	_, err = os.Stat(versionsDir)
+	versionsDir := ".stversions"
+	_, err = v.fs.Stat(versionsDir)
 	if err != nil {
-		if os.IsNotExist(err) {
-			l.Debugln("creating versions dir", versionsDir)
-			osutil.MkdirAll(versionsDir, 0755)
-			osutil.HideFile(versionsDir)
+		if fs.IsNotExist(err) {
+			l.Debugln("creating versions dir .stversions")
+			v.fs.Mkdir(versionsDir, 0755)
+			v.fs.Hide(versionsDir)
 		} else {
 			return err
 		}
@@ -66,28 +69,25 @@ func (v Simple) Archive(filePath string) error {
 	l.Debugln("archiving", filePath)
 
 	file := filepath.Base(filePath)
-	inFolderPath, err := filepath.Rel(v.folderPath, filepath.Dir(filePath))
-	if err != nil {
-		return err
-	}
+	inFolderPath := filepath.Dir(filePath)
 
 	dir := filepath.Join(versionsDir, inFolderPath)
-	err = osutil.MkdirAll(dir, 0755)
-	if err != nil && !os.IsExist(err) {
+	err = v.fs.MkdirAll(dir, 0755)
+	if err != nil && !fs.IsExist(err) {
 		return err
 	}
 
-	ver := taggedFilename(file, fileInfo.ModTime().Format(TimeFormat))
+	ver := taggedFilename(file, info.ModTime().Format(TimeFormat))
 	dst := filepath.Join(dir, ver)
 	l.Debugln("moving to", dst)
-	err = osutil.Rename(filePath, dst)
+	err = osutil.Rename(v.fs, filePath, dst)
 	if err != nil {
 		return err
 	}
 
 	// Glob according to the new file~timestamp.ext pattern.
 	pattern := filepath.Join(dir, taggedFilename(file, TimeGlob))
-	newVersions, err := osutil.Glob(pattern)
+	newVersions, err := v.fs.Glob(pattern)
 	if err != nil {
 		l.Warnln("globbing:", err, "for", pattern)
 		return nil
@@ -95,7 +95,7 @@ func (v Simple) Archive(filePath string) error {
 
 	// Also according to the old file.ext~timestamp pattern.
 	pattern = filepath.Join(dir, file+"~"+TimeGlob)
-	oldVersions, err := osutil.Glob(pattern)
+	oldVersions, err := v.fs.Glob(pattern)
 	if err != nil {
 		l.Warnln("globbing:", err, "for", pattern)
 		return nil
@@ -108,7 +108,7 @@ func (v Simple) Archive(filePath string) error {
 	if len(versions) > v.keep {
 		for _, toRemove := range versions[:len(versions)-v.keep] {
 			l.Debugln("cleaning out", toRemove)
-			err = os.Remove(toRemove)
+			err = v.fs.Remove(toRemove)
 			if err != nil {
 				l.Warnln("removing old version:", err)
 			}

lib/versioner/simple_test.go

@@ -9,10 +9,11 @@ package versioner
 import (
 	"io/ioutil"
 	"math"
-	"os"
 	"path/filepath"
 	"testing"
 	"time"
+
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func TestTaggedFilename(t *testing.T) {
@@ -53,29 +54,28 @@ func TestSimpleVersioningVersionCount(t *testing.T) {
 	}
 
 	dir, err := ioutil.TempDir("", "")
-	defer os.RemoveAll(dir)
+	//defer os.RemoveAll(dir)
 	if err != nil {
 		t.Error(err)
 	}
 
-	v := NewSimple("", dir, map[string]string{"keep": "2"})
-	versionDir := filepath.Join(dir, ".stversions")
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 
-	path := filepath.Join(dir, "test")
+	v := NewSimple("", fs, map[string]string{"keep": "2"})
+
+	path := "test"
 
 	for i := 1; i <= 3; i++ {
-		f, err := os.Create(path)
+		f, err := fs.Create(path)
 		if err != nil {
 			t.Error(err)
 		}
 		f.Close()
-		v.Archive(path)
-
-		d, err := os.Open(versionDir)
-		if err != nil {
+		if err := v.Archive(path); err != nil {
 			t.Error(err)
 		}
-		n, err := d.Readdirnames(-1)
+
+		n, err := fs.DirNames(".stversions")
 		if err != nil {
 			t.Error(err)
 		}
@@ -83,7 +83,6 @@ func TestSimpleVersioningVersionCount(t *testing.T) {
 		if float64(len(n)) != math.Min(float64(i), 2) {
 			t.Error("Wrong count")
 		}
-		d.Close()
 
 		time.Sleep(time.Second)
 	}

lib/versioner/staggered.go

@@ -12,7 +12,7 @@ import (
 	"strconv"
 	"time"
 
-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/sync"
 	"github.com/syncthing/syncthing/lib/util"
 )
@@ -28,9 +28,9 @@ type Interval struct {
 }
 
 type Staggered struct {
-	versionsPath  string
 	cleanInterval int64
-	folderPath    string
+	folderFs      fs.Filesystem
+	versionsFs    fs.Filesystem
 	interval      [4]Interval
 	mutex         sync.Mutex
 
@@ -38,7 +38,7 @@ type Staggered struct {
 	testCleanDone chan struct{}
 }
 
-func NewStaggered(folderID, folderPath string, params map[string]string) Versioner {
+func NewStaggered(folderID string, folderFs fs.Filesystem, params map[string]string) Versioner {
 	maxAge, err := strconv.ParseInt(params["maxAge"], 10, 0)
 	if err != nil {
 		maxAge = 31536000 // Default: ~1 year
@@ -49,22 +49,20 @@ func NewStaggered(folderID, folderPath string, params map[string]string) Version
 	}
 
 	// Use custom path if set, otherwise .stversions in folderPath
-	var versionsDir string
+	var versionsFs fs.Filesystem
 	if params["versionsPath"] == "" {
-		versionsDir = filepath.Join(folderPath, ".stversions")
-		l.Debugln("using default dir .stversions")
+		versionsFs = fs.NewFilesystem(folderFs.Type(), filepath.Join(folderFs.URI(), ".stversions"))
 	} else if filepath.IsAbs(params["versionsPath"]) {
-		l.Debugln("using dir", params["versionsPath"])
-		versionsDir = params["versionsPath"]
+		versionsFs = fs.NewFilesystem(folderFs.Type(), params["versionsPath"])
 	} else {
-		versionsDir = filepath.Join(folderPath, params["versionsPath"])
-		l.Debugln("using dir", versionsDir)
+		versionsFs = fs.NewFilesystem(folderFs.Type(), filepath.Join(folderFs.URI(), params["versionsPath"]))
 	}
+	l.Debugln("%s folder using %s (%s) staggered versioner dir", folderID, versionsFs.URI(), versionsFs.Type())
 
 	s := &Staggered{
-		versionsPath:  versionsDir,
 		cleanInterval: cleanInterval,
-		folderPath:    folderPath,
+		folderFs:      folderFs,
+		versionsFs:    versionsFs,
 		interval: [4]Interval{
 			{30, 3600},       // first hour -> 30 sec between versions
 			{3600, 86400},    // next day -> 1 h between versions
@@ -102,12 +100,12 @@ func (v *Staggered) Stop() {
 }
 
 func (v *Staggered) clean() {
-	l.Debugln("Versioner clean: Waiting for lock on", v.versionsPath)
+	l.Debugln("Versioner clean: Waiting for lock on", v.versionsFs)
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
-	l.Debugln("Versioner clean: Cleaning", v.versionsPath)
+	l.Debugln("Versioner clean: Cleaning", v.versionsFs)
 
-	if _, err := os.Stat(v.versionsPath); os.IsNotExist(err) {
+	if _, err := v.versionsFs.Stat("."); fs.IsNotExist(err) {
 		// There is no need to clean a nonexistent dir.
 		return
 	}
@@ -115,14 +113,14 @@ func (v *Staggered) clean() {
 	versionsPerFile := make(map[string][]string)
 	filesPerDir := make(map[string]int)
 
-	err := filepath.Walk(v.versionsPath, func(path string, f os.FileInfo, err error) error {
+	err := v.versionsFs.Walk(".", func(path string, f fs.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
 
-		if f.Mode().IsDir() && f.Mode()&os.ModeSymlink == 0 {
+		if f.IsDir() && !f.IsSymlink() {
 			filesPerDir[path] = 0
-			if path != v.versionsPath {
+			if path != "." {
 				dir := filepath.Dir(path)
 				filesPerDir[dir]++
 			}
@@ -155,25 +153,20 @@ func (v *Staggered) clean() {
 			continue
 		}
 
-		if path == v.versionsPath {
-			l.Debugln("Cleaner: versions dir is empty, don't delete", path)
-			continue
-		}
-
 		l.Debugln("Cleaner: deleting empty directory", path)
-		err = os.Remove(path)
+		err = v.versionsFs.Remove(path)
 		if err != nil {
 			l.Warnln("Versioner: can't remove directory", path, err)
 		}
 	}
 
-	l.Debugln("Cleaner: Finished cleaning", v.versionsPath)
+	l.Debugln("Cleaner: Finished cleaning", v.versionsFs)
 }
 
 func (v *Staggered) expire(versions []string) {
 	l.Debugln("Versioner: Expiring versions", versions)
 	for _, file := range v.toRemove(versions, time.Now()) {
-		if fi, err := osutil.Lstat(file); err != nil {
+		if fi, err := v.versionsFs.Lstat(file); err != nil {
 			l.Warnln("versioner:", err)
 			continue
 		} else if fi.IsDir() {
@@ -181,7 +174,7 @@ func (v *Staggered) expire(versions []string) {
 			continue
 		}
 
-		if err := os.Remove(file); err != nil {
+		if err := v.versionsFs.Remove(file); err != nil {
 			l.Warnf("Versioner: can't remove %q: %v", file, err)
 		}
 	}
@@ -203,7 +196,7 @@ func (v *Staggered) toRemove(versions []string, now time.Time) []string {
 		// If the file is older than the max age of the last interval, remove it
 		if lastIntv := v.interval[len(v.interval)-1]; lastIntv.end > 0 && age > lastIntv.end {
 			l.Debugln("Versioner: File over maximum age -> delete ", file)
-			err = os.Remove(file)
+			err = v.versionsFs.Remove(file)
 			if err != nil {
 				l.Warnf("Versioner: can't remove %q: %v", file, err)
 			}
@@ -240,23 +233,26 @@ func (v *Staggered) toRemove(versions []string, now time.Time) []string {
 // Archive moves the named file away to a version archive. If this function
 // returns nil, the named file does not exist any more (has been archived).
 func (v *Staggered) Archive(filePath string) error {
-	l.Debugln("Waiting for lock on ", v.versionsPath)
+	l.Debugln("Waiting for lock on ", v.versionsFs)
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
 
-	_, err := osutil.Lstat(filePath)
-	if os.IsNotExist(err) {
+	info, err := v.folderFs.Lstat(filePath)
+	if fs.IsNotExist(err) {
 		l.Debugln("not archiving nonexistent file", filePath)
 		return nil
 	} else if err != nil {
 		return err
 	}
+	if info.IsSymlink() {
+		panic("bug: attempting to version a symlink")
+	}
 
-	if _, err := os.Stat(v.versionsPath); err != nil {
-		if os.IsNotExist(err) {
-			l.Debugln("creating versions dir", v.versionsPath)
-			osutil.MkdirAll(v.versionsPath, 0755)
-			osutil.HideFile(v.versionsPath)
+	if _, err := v.versionsFs.Stat("."); err != nil {
+		if fs.IsNotExist(err) {
+			l.Debugln("creating versions dir", v.versionsFs)
+			v.versionsFs.MkdirAll(".", 0755)
+			v.versionsFs.Hide(".")
 		} else {
 			return err
 		}
@@ -265,36 +261,41 @@ func (v *Staggered) Archive(filePath string) error {
 	l.Debugln("archiving", filePath)
 
 	file := filepath.Base(filePath)
-	inFolderPath, err := filepath.Rel(v.folderPath, filepath.Dir(filePath))
+	inFolderPath := filepath.Dir(filePath)
 	if err != nil {
 		return err
 	}
 
-	dir := filepath.Join(v.versionsPath, inFolderPath)
-	err = osutil.MkdirAll(dir, 0755)
-	if err != nil && !os.IsExist(err) {
+	err = v.versionsFs.MkdirAll(inFolderPath, 0755)
+	if err != nil && !fs.IsExist(err) {
 		return err
 	}
 
 	ver := taggedFilename(file, time.Now().Format(TimeFormat))
-	dst := filepath.Join(dir, ver)
+	dst := filepath.Join(inFolderPath, ver)
 	l.Debugln("moving to", dst)
-	err = osutil.Rename(filePath, dst)
+
+	/// TODO: Fix this when we have an alternative filesystem implementation
+	if v.versionsFs.Type() != fs.FilesystemTypeBasic {
+		panic("bug: staggered versioner used with unsupported filesystem")
+	}
+
+	err = os.Rename(filepath.Join(v.folderFs.URI(), filePath), filepath.Join(v.versionsFs.URI(), dst))
 	if err != nil {
 		return err
 	}
 
 	// Glob according to the new file~timestamp.ext pattern.
-	pattern := filepath.Join(dir, taggedFilename(file, TimeGlob))
-	newVersions, err := osutil.Glob(pattern)
+	pattern := filepath.Join(inFolderPath, taggedFilename(file, TimeGlob))
+	newVersions, err := v.versionsFs.Glob(pattern)
 	if err != nil {
 		l.Warnln("globbing:", err, "for", pattern)
 		return nil
 	}
 
 	// Also according to the old file.ext~timestamp pattern.
-	pattern = filepath.Join(dir, file+"~"+TimeGlob)
-	oldVersions, err := osutil.Glob(pattern)
+	pattern = filepath.Join(inFolderPath, file+"~"+TimeGlob)
+	oldVersions, err := v.versionsFs.Glob(pattern)
 	if err != nil {
 		l.Warnln("globbing:", err, "for", pattern)
 		return nil

lib/versioner/staggered_test.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/d4l3k/messagediff"
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func TestStaggeredVersioningVersionCount(t *testing.T) {
@@ -62,7 +63,7 @@ func TestStaggeredVersioningVersionCount(t *testing.T) {
 	os.MkdirAll("testdata/.stversions", 0755)
 	defer os.RemoveAll("testdata")
 
-	v := NewStaggered("", "testdata", map[string]string{"maxAge": strconv.Itoa(365 * 86400)}).(*Staggered)
+	v := NewStaggered("", fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"), map[string]string{"maxAge": strconv.Itoa(365 * 86400)}).(*Staggered)
 	v.testCleanDone = make(chan struct{})
 	defer v.Stop()
 	go v.Serve()

lib/versioner/trashcan.go

@@ -8,11 +8,11 @@ package versioner
 
 import (
 	"fmt"
-	"os"
 	"path/filepath"
 	"strconv"
 	"time"
 
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/osutil"
 )
 
@@ -22,17 +22,17 @@ func init() {
 }
 
 type Trashcan struct {
-	folderPath   string
+	fs           fs.Filesystem
 	cleanoutDays int
 	stop         chan struct{}
 }
 
-func NewTrashcan(folderID, folderPath string, params map[string]string) Versioner {
+func NewTrashcan(folderID string, fs fs.Filesystem, params map[string]string) Versioner {
 	cleanoutDays, _ := strconv.Atoi(params["cleanoutDays"])
 	// On error we default to 0, "do not clean out the trash can"
 
 	s := &Trashcan{
-		folderPath:   folderPath,
+		fs:           fs,
 		cleanoutDays: cleanoutDays,
 		stop:         make(chan struct{}),
 	}
@@ -44,49 +44,47 @@ func NewTrashcan(folderID, folderPath string, params map[string]string) Versione
 // Archive moves the named file away to a version archive. If this function
 // returns nil, the named file does not exist any more (has been archived).
 func (t *Trashcan) Archive(filePath string) error {
-	_, err := osutil.Lstat(filePath)
-	if os.IsNotExist(err) {
+	info, err := t.fs.Lstat(filePath)
+	if fs.IsNotExist(err) {
 		l.Debugln("not archiving nonexistent file", filePath)
 		return nil
 	} else if err != nil {
 		return err
 	}
+	if info.IsSymlink() {
+		panic("bug: attempting to version a symlink")
+	}
 
-	versionsDir := filepath.Join(t.folderPath, ".stversions")
-	if _, err := os.Stat(versionsDir); err != nil {
-		if !os.IsNotExist(err) {
+	versionsDir := ".stversions"
+	if _, err := t.fs.Stat(versionsDir); err != nil {
+		if !fs.IsNotExist(err) {
 			return err
 		}
 
 		l.Debugln("creating versions dir", versionsDir)
-		if err := osutil.MkdirAll(versionsDir, 0777); err != nil {
+		if err := t.fs.MkdirAll(versionsDir, 0777); err != nil {
 			return err
 		}
-		osutil.HideFile(versionsDir)
+		t.fs.Hide(versionsDir)
 	}
 
 	l.Debugln("archiving", filePath)
 
-	relativePath, err := filepath.Rel(t.folderPath, filePath)
-	if err != nil {
-		return err
-	}
-
-	archivedPath := filepath.Join(versionsDir, relativePath)
-	if err := osutil.MkdirAll(filepath.Dir(archivedPath), 0777); err != nil && !os.IsExist(err) {
+	archivedPath := filepath.Join(versionsDir, filePath)
+	if err := t.fs.MkdirAll(filepath.Dir(archivedPath), 0777); err != nil && !fs.IsExist(err) {
 		return err
 	}
 
 	l.Debugln("moving to", archivedPath)
 
-	if err := osutil.Rename(filePath, archivedPath); err != nil {
+	if err := osutil.Rename(t.fs, filePath, archivedPath); err != nil {
 		return err
 	}
 
 	// Set the mtime to the time the file was deleted. This is used by the
 	// cleanout routine. If this fails things won't work optimally but there's
 	// not much we can do about it so we ignore the error.
-	os.Chtimes(archivedPath, time.Now(), time.Now())
+	t.fs.Chtimes(archivedPath, time.Now(), time.Now())
 
 	return nil
 }
@@ -126,15 +124,15 @@ func (t *Trashcan) String() string {
 }
 
 func (t *Trashcan) cleanoutArchive() error {
-	versionsDir := filepath.Join(t.folderPath, ".stversions")
-	if _, err := osutil.Lstat(versionsDir); os.IsNotExist(err) {
+	versionsDir := ".stversions"
+	if _, err := t.fs.Lstat(versionsDir); fs.IsNotExist(err) {
 		return nil
 	}
 
 	cutoff := time.Now().Add(time.Duration(-24*t.cleanoutDays) * time.Hour)
 	currentDir := ""
 	filesInDir := 0
-	walkFn := func(path string, info os.FileInfo, err error) error {
+	walkFn := func(path string, info fs.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
@@ -144,7 +142,7 @@ func (t *Trashcan) cleanoutArchive() error {
 			// directory was empty and try to remove it. We ignore failure for
 			// the time being.
 			if currentDir != "" && filesInDir == 0 {
-				os.Remove(currentDir)
+				t.fs.Remove(currentDir)
 			}
 			currentDir = path
 			filesInDir = 0
@@ -153,7 +151,7 @@ func (t *Trashcan) cleanoutArchive() error {
 
 		if info.ModTime().Before(cutoff) {
 			// The file is too old; remove it.
-			os.Remove(path)
+			t.fs.Remove(path)
 		} else {
 			// Keep this file, and remember it so we don't unnecessarily try
 			// to remove this directory.
@@ -162,14 +160,14 @@ func (t *Trashcan) cleanoutArchive() error {
 		return nil
 	}
 
-	if err := filepath.Walk(versionsDir, walkFn); err != nil {
+	if err := t.fs.Walk(versionsDir, walkFn); err != nil {
 		return err
 	}
 
 	// The last directory seen by the walkFn may not have been removed as it
 	// should be.
 	if currentDir != "" && filesInDir == 0 {
-		os.Remove(currentDir)
+		t.fs.Remove(currentDir)
 	}
 	return nil
 }

lib/versioner/trashcan_test.go

@@ -12,6 +12,8 @@ import (
 	"path/filepath"
 	"testing"
 	"time"
+
+	"github.com/syncthing/syncthing/lib/fs"
 )
 
 func TestTrashcanCleanout(t *testing.T) {
@@ -49,7 +51,7 @@ func TestTrashcanCleanout(t *testing.T) {
 		}
 	}
 
-	versioner := NewTrashcan("default", "testdata", map[string]string{"cleanoutDays": "7"}).(*Trashcan)
+	versioner := NewTrashcan("default", fs.NewFilesystem(fs.FilesystemTypeBasic, "testdata"), map[string]string{"cleanoutDays": "7"}).(*Trashcan)
 	if err := versioner.cleanoutArchive(); err != nil {
 		t.Fatal(err)
 	}

lib/versioner/versioner.go

@@ -8,11 +8,13 @@
 // simple default versioning scheme.
 package versioner
 
+import "github.com/syncthing/syncthing/lib/fs"
+
 type Versioner interface {
 	Archive(filePath string) error
 }
 
-var Factories = map[string]func(folderID string, folderDir string, params map[string]string) Versioner{}
+var Factories = map[string]func(folderID string, filesystem fs.Filesystem, params map[string]string) Versioner{}
 
 const (
 	TimeFormat = "20060102-150405"

lib/weakhash/weakhash.go

@@ -9,7 +9,6 @@ package weakhash
 import (
 	"bufio"
 	"io"
-	"os"
 
 	"github.com/chmduquesne/rollinghash/adler32"
 )
@@ -72,27 +71,21 @@ func Find(ir io.Reader, hashesToFind []uint32, size int) (map[uint32][]int64, er
 	return offsets, nil
 }
 
-func NewFinder(path string, size int, hashesToFind []uint32) (*Finder, error) {
-	file, err := os.Open(path)
+func NewFinder(ir io.ReadSeeker, size int, hashesToFind []uint32) (*Finder, error) {
+	offsets, err := Find(ir, hashesToFind, size)
 	if err != nil {
 		return nil, err
 	}
 
-	offsets, err := Find(file, hashesToFind, size)
-	if err != nil {
-		file.Close()
-		return nil, err
-	}
-
 	return &Finder{
-		file:    file,
+		reader:  ir,
 		size:    size,
 		offsets: offsets,
 	}, nil
 }
 
 type Finder struct {
-	file    *os.File
+	reader  io.ReadSeeker
 	size    int
 	offsets map[uint32][]int64
 }
@@ -106,7 +99,11 @@ func (h *Finder) Iterate(hash uint32, buf []byte, iterFunc func(int64) bool) (bo
 	}
 
 	for _, offset := range h.offsets[hash] {
-		_, err := h.file.ReadAt(buf, offset)
+		_, err := h.reader.Seek(offset, io.SeekStart)
+		if err != nil {
+			return false, err
+		}
+		_, err = h.reader.Read(buf)
 		if err != nil {
 			return false, err
 		}
@@ -116,10 +113,3 @@ func (h *Finder) Iterate(hash uint32, buf []byte, iterFunc func(int64) bool) (bo
 	}
 	return false, nil
 }
-
-// Close releases any resource associated with the finder
-func (h *Finder) Close() {
-	if h != nil {
-		h.file.Close()
-	}
-}

lib/weakhash/weakhash_test.go

@@ -11,6 +11,7 @@ package weakhash
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
 	"os"
 	"reflect"
@@ -30,13 +31,15 @@ func TestFinder(t *testing.T) {
 	if _, err := f.Write(payload); err != nil {
 		t.Error(err)
 	}
+	if _, err := f.Seek(0, io.SeekStart); err != nil {
+		t.Error(err)
+	}
 
 	hashes := []uint32{65143183, 65798547}
-	finder, err := NewFinder(f.Name(), 4, hashes)
+	finder, err := NewFinder(f, 4, hashes)
 	if err != nil {
 		t.Error(err)
 	}
-	defer finder.Close()
 
 	expected := map[uint32][]int64{
 		65143183: {1, 27, 53, 79},

man/stdiscosrv.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "STDISCOSRV" "1" "July 03, 2017" "v0.14" "Syncthing"
+.TH "STDISCOSRV" "1" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 stdiscosrv \- Syncthing Discovery Server
 .

man/strelaysrv.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "STRELAYSRV" "1" "July 03, 2017" "v0.14" "Syncthing"
+.TH "STRELAYSRV" "1" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 strelaysrv \- Syncthing Relay Server
 .
@@ -144,6 +144,7 @@ An optional description about who provides the relay.
 .TP
 .B \-status\-srv=<listen addr>
 Listen address for status service (blank to disable) (default ":22070").
+Status service is used by the relay pool server UI for displaying stats (data transfered, number of clients, etc.)
 .UNINDENT
 .SH SETTING UP
 .sp

man/syncthing-bep.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-BEP" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-BEP" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-bep \- Block Exchange Protocol v1
 .

man/syncthing-config.5

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-CONFIG" "5" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-CONFIG" "5" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-config \- Syncthing Configuration
 .
@@ -655,7 +655,7 @@ slow response time (slow connection/cpu) and large index exchanges.
 Ping interval in seconds. Don\(aqt change it unless you feel it\(aqs necessary.
 .TP
 .B minHomeDiskFree
-The minimum required free space that should be available on the the
+The minimum required free space that should be available on the
 partition holding the configuration and index. Accepted units are \fB%\fP, \fBkB\fP,
 \fBMB\fP, \fBGB\fP and \fBTB\fP\&.
 .TP

man/syncthing-device-ids.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-DEVICE-IDS" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-DEVICE-IDS" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-device-ids \- Understanding Device IDs
 .

man/syncthing-event-api.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-EVENT-API" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-EVENT-API" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-event-api \- Event API
 .

man/syncthing-faq.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-FAQ" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-FAQ" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-faq \- Frequently Asked Questions
 .
@@ -424,6 +424,28 @@ Syncthing logs to stdout by default. On Windows Syncthing by default also
 creates \fBsyncthing.log\fP in Syncthing\(aqs home directory (run \fBsyncthing
 \-paths\fP to see where that is). Command line option \fB\-logfile\fP can be used
 to specify a user\-defined logfile.
+.SS How can I view the history of changes?
+.sp
+The web GUI contains a \fBGlobal Changes\fP button under the device list which
+displays changes since the last (re)start of Syncthing. With the \fB\-audit\fP
+option you can enable a persistent, detailed log of changes and most
+activities, which contains a \fBJSON\fP formatted  sequence of events in the
+\fB~/.config/syncthing/audit\-_date_\-_time_.log\fP file.
+.SS Does the audit log contain every change?
+.sp
+The audit log (and the \fBGlobal Changes\fP window) sees the changes that your
+Syncthing sees. When Syncthing is continuously connected it usually sees every change
+happening immediately and thus knows which node initiated the change.
+When topology gets complex or when your node reconnects after some time offline,
+Syncthing synchronises with its neighbours: It gets the latest synchronised state
+from the neighbour, which is the \fIresult\fP of all the changes between the last
+known state (before disconnect or network delay) and the current state at the
+neighbour, and if there were updates, deletes, creates, conflicts, which were
+overlapping we only see the \fIlatest change\fP for a given file or directory (and
+the node where that latest change occurred). When we connect to multiple neighbours
+Syncthing decides which neighbor has the latest state, or if the states conflict
+it initiates the conflict resolution procedure, which in the end results in a consistent
+up\-to\-date state with all the neighbours.
 .SS How do I upgrade Syncthing?
 .sp
 If you use a package manager such as Debian\(aqs apt\-get, you should upgrade

man/syncthing-globaldisco.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-GLOBALDISCO" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-GLOBALDISCO" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-globaldisco \- Global Discovery Protocol v3
 .

man/syncthing-localdisco.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-LOCALDISCO" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-LOCALDISCO" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-localdisco \- Local Discovery Protocol v4
 .

man/syncthing-networking.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-NETWORKING" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-NETWORKING" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-networking \- Firewall Setup
 .

man/syncthing-relay.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-RELAY" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-RELAY" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-relay \- Relay Protocol v1
 .
@@ -99,7 +99,7 @@ which then can be used to establish a connection in session mode.
 .sp
 If the client fails to send a JoinRelayRequest message within the first ping
 interval, the connection is terminated.
-If the client fails to send a message (even if its a ping message) every minute
+If the client fails to send a message (even if it\(aqs a ping message) every minute
 (by default), the connection is terminated.
 .SS Temporary protocol submode
 .sp

man/syncthing-rest-api.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-REST-API" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-REST-API" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-rest-api \- REST API
 .
@@ -45,6 +45,49 @@ the configuration file. To use an API key, set the request header
 "X\-API\-Key: abc123" http://localhost:8384/rest/...\fP can be used to invoke
 with \fBcurl\fP\&.
 .SH SYSTEM ENDPOINTS
+.SS GET /rest/system/browse
+.sp
+Returns a list of directories matching the path given by the optional parameter
+\fBcurrent\fP\&. The path can use \fI\%patterns as described in Go\(aqs filepath package\fP <\fBhttps://golang.org/pkg/path/filepath/#Match\fP>\&. A \(aq*\(aq will always be appended
+to the given path (e.g. \fB/tmp/\fP matches all its subdirectories). If the option
+\fBcurrent\fP is not given, filesystem root paths are returned.
+.INDENT 0.0
+.INDENT 3.5
+.sp
+.nf
+.ft C
+$ curl \-H "X\-API\-Key: yourkey" localhost:8384/rest/system/browse | json_pp
+[
+    "/"
+]
+
+$ curl \-H "X\-API\-Key: yourkey" localhost:8384/rest/system/browse?current=/var/ | json_pp
+[
+    "/var/backups/",
+    "/var/cache/",
+    "/var/lib/",
+    "/var/local/",
+    "/var/lock/",
+    "/var/log/",
+    "/var/mail/",
+    "/var/opt/",
+    "/var/run/",
+    "/var/spool/",
+    "/var/tmp/"
+]
+
+$ curl \-H "X\-API\-Key: yourkey" localhost:8384/rest/system/browse?current=/var/*o | json_pp
+[
+    "/var/local/",
+    "/var/lock/",
+    "/var/log/",
+    "/var/opt/",
+    "/var/spool/"
+]
+.ft P
+.fi
+.UNINDENT
+.UNINDENT
 .SS GET /rest/system/config
 .sp
 Returns the current configuration.
@@ -407,7 +450,7 @@ Returns the list of recent log entries.
 .sp
 Pause the given device or all devices.
 .sp
-Takes the optional parameter \fBdevice\fP (device ID). When ommitted,
+Takes the optional parameter \fBdevice\fP (device ID). When omitted,
 pauses all devices.  Returns status 200 and no content upon success, or status
 500 and a plain text error on failure.
 .SS GET /rest/system/ping
@@ -451,7 +494,7 @@ Post with empty body to immediately restart Syncthing.
 .sp
 Resume the given device or all devices.
 .sp
-Takes the optional parameter \fBdevice\fP (device ID). When ommitted,
+Takes the optional parameter \fBdevice\fP (device ID). When omitted,
 resumes all devices.  Returns status 200 and no content upon success, or status
 500 and a plain text error on failure.
 .SS POST /rest/system/shutdown

man/syncthing-security.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-SECURITY" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-SECURITY" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-security \- Security Principles
 .

man/syncthing-stignore.5

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-STIGNORE" "5" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-STIGNORE" "5" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-stignore \- Prevent files from being synchronized to other nodes
 .
@@ -116,7 +116,8 @@ Windows does not support escaping \fB\e[foo \- bar\e]\fP\&.
 \fBNOTE:\fP
 .INDENT 0.0
 .INDENT 3.5
-Prefixes can be specified in any order.
+Prefixes can be specified in any order (e.g. "(?d)(?i)"), but cannot be in a
+single pair of parentheses (not "(?di)").
 .UNINDENT
 .UNINDENT
 .SH EXAMPLE

man/syncthing-versioning.7

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "SYNCTHING-VERSIONING" "7" "July 03, 2017" "v0.14" "Syncthing"
+.TH "SYNCTHING-VERSIONING" "7" "August 19, 2017" "v0.14" "Syncthing"
 .SH NAME
 syncthing-versioning \- Keep automatic backups of deleted files by other nodes
 .
@@ -35,8 +35,8 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 Syncthing supports archiving the old version of a file when it is deleted or
 replaced with a newer version from the cluster. This is called "file
 versioning" and uses one of the available \fIversioning strategies\fP described
-below. File versioning is configured per folder and defaults to "no file
-versioning", i.e. no old copies of files are kept.
+below. File versioning is configured per folder, on a per\-device basis, and
+defaults to "no file versioning", i.e. no old copies of files are kept.
 .SH TRASH CAN FILE VERSIONING
 .sp
 This versioning strategy emulates the common "trash can" approach. When a file
@@ -97,10 +97,17 @@ only for 10 days, use 10. \fBNote: Set to 0 to keep versions forever.\fP
 .SH EXTERNAL FILE VERSIONING
 .sp
 This versioning method delegates the decision on what to do to an external
-command (program or script). The only configuration option is the name of the
-command. This should be an absolute path name. Just prior to a file being
-replaced, the command will be run with two parameters: the path to the folder,
-and the path to the file within the folder.
+command (program or script).
+Just prior to a file being replaced, the command will be run.
+The command should be specified as an absolute path, and can use the following templated arguments:
+.INDENT 0.0
+.TP
+.B %FOLDER_PATH%
+Path to the folder
+.TP
+.B %FILE_PATH%
+Path to the file within the folder
+.UNINDENT
 .SS Example for Unixes
 .sp
 Lets say I want to keep the latest version of each file as they are replaced
@@ -133,8 +140,7 @@ mv \-f "$folderpath/$filepath" "$versionspath/$filepath"
 .UNINDENT
 .sp
 I must ensure that the script has execute permissions (\fBchmod 755
-onlylatest.sh\fP), then configure Syncthing with the above path as the command
-name.
+onlylatest.sh\fP), then configure Syncthing with command \fB/Users/jb/bin/onlylatest.sh %FOLDER_PATH% %FILE_PATH%\fP
 .sp
 Lets assume I have a folder "default" in ~/Sync, and that within that folder
 there is a file \fBdocs/letter.txt\fP that is being replaced or deleted. The
@@ -186,7 +192,7 @@ move /Y "%FOLDER_PATH%\e%FILE_PATH%" "%VERSIONS_PATH%\e%FILE_PATH%"
 .UNINDENT
 .UNINDENT
 .sp
-Finally, I set \fBC:\eUsers\emfrnd\eScripts\eonlylatest.bat\fP as command name in
+Finally, I set \fBC:\eUsers\emfrnd\eScripts\eonlylatest.bat %FOLDER_PATH% %FILE_PATH%\fP as command name in
 Syncthing.
 .SH AUTHOR
 The Syncthing Authors