Create missing directories

lib/model/sharedpullerstate.go

@@ -86,8 +86,24 @@ func (s *sharedPullerState) tempFile() (io.WriterAt, error) {
 	// here.
 	dir := filepath.Dir(s.tempName)
 	if info, err := os.Stat(dir); err != nil {
-		s.failLocked("dst stat dir", err)
-		return nil, err
+		if os.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
+			// file "foo/bar" that we want to sync. We never create the
+			// directory, and hence fail to create the file and end up looping
+			// forever on it. This breaks that by creating the directory; on
+			// 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 {
+				s.failLocked("resurrect dir", err)
+				return nil, err
+			}
+		} else {
+			s.failLocked("dst stat dir", err)
+			return nil, err
+		}
 	} else if info.Mode()&0200 == 0 {
 		err := os.Chmod(dir, 0755)
 		if !s.ignorePerms && err == nil {