diff --git a/cmd/cmount/fs.go b/cmd/cmount/fs.go
index d3f992514..ae91e91ab 100644
--- a/cmd/cmount/fs.go
+++ b/cmd/cmount/fs.go
@@ -289,41 +289,65 @@ func (fsys *FS) Statfs(path string, stat *fuse.Statfs_t) (errc int) {
 	return 0
 }
 
-// Open opens a file
-func (fsys *FS) Open(path string, flags int) (errc int, fh uint64) {
-	defer log.Trace(path, "flags=0x%X", flags)("errc=%d, fh=0x%X", &errc, &fh)
+// OpenEx opens a file
+func (fsys *FS) OpenEx(path string, fi *fuse.FileInfo_t) (errc int) {
+	defer log.Trace(path, "flags=0x%X", fi.Flags)("errc=%d, fh=0x%X", &errc, &fi.Fh)
+	fi.Fh = fhUnset
 
 	// translate the fuse flags to os flags
-	flags = translateOpenFlags(flags)
+	flags := translateOpenFlags(fi.Flags)
 	handle, err := fsys.VFS.OpenFile(path, flags, 0777)
 	if err != nil {
-		return translateError(err), fhUnset
+		return translateError(err)
 	}
 
-	// FIXME add support for unknown length files setting direct_io
-	// See: https://github.com/billziss-gh/cgofuse/issues/38
+	// If size unknown then use direct io to read
+	if entry := handle.Node().DirEntry(); entry != nil && entry.Size() < 0 {
+		fi.DirectIo = true
+	}
 
-	return 0, fsys.openHandle(handle)
+	fi.Fh = fsys.openHandle(handle)
+	return 0
+}
+
+// Open opens a file
+func (fsys *FS) Open(path string, flags int) (errc int, fh uint64) {
+	var fi = fuse.FileInfo_t{
+		Flags: flags,
+	}
+	errc = fsys.OpenEx(path, &fi)
+	return errc, fi.Fh
+}
+
+// CreateEx creates and opens a file.
+func (fsys *FS) CreateEx(filePath string, mode uint32, fi *fuse.FileInfo_t) (errc int) {
+	defer log.Trace(filePath, "flags=0x%X, mode=0%o", fi.Flags, mode)("errc=%d, fh=0x%X", &errc, &fi.Fh)
+	fi.Fh = fhUnset
+	leaf, parentDir, errc := fsys.lookupParentDir(filePath)
+	if errc != 0 {
+		return errc
+	}
+	file, err := parentDir.Create(leaf, fi.Flags)
+	if err != nil {
+		return translateError(err)
+	}
+	// translate the fuse flags to os flags
+	flags := translateOpenFlags(fi.Flags) | os.O_CREATE
+	handle, err := file.Open(flags)
+	if err != nil {
+		return translateError(err)
+	}
+	fi.Fh = fsys.openHandle(handle)
+	return 0
 }
 
 // Create creates and opens a file.
 func (fsys *FS) Create(filePath string, flags int, mode uint32) (errc int, fh uint64) {
-	defer log.Trace(filePath, "flags=0x%X, mode=0%o", flags, mode)("errc=%d, fh=0x%X", &errc, &fh)
-	leaf, parentDir, errc := fsys.lookupParentDir(filePath)
-	if errc != 0 {
-		return errc, fhUnset
+	var fi = fuse.FileInfo_t{
+		Flags: flags,
 	}
-	file, err := parentDir.Create(leaf, flags)
-	if err != nil {
-		return translateError(err), fhUnset
-	}
-	// translate the fuse flags to os flags
-	flags = translateOpenFlags(flags) | os.O_CREATE
-	handle, err := file.Open(flags)
-	if err != nil {
-		return translateError(err), fhUnset
-	}
-	return 0, fsys.openHandle(handle)
+	errc = fsys.CreateEx(filePath, mode, &fi)
+	return errc, fi.Fh
 }
 
 // Truncate truncates a file to size
@@ -594,3 +618,12 @@ func translateOpenFlags(inFlags int) (outFlags int) {
 	// NB O_SYNC isn't defined by fuse
 	return outFlags
 }
+
+// Make sure interfaces are satisfied
+var (
+	_ fuse.FileSystemInterface = (*FS)(nil)
+	_ fuse.FileSystemOpenEx    = (*FS)(nil)
+	//_ fuse.FileSystemChflags    = (*FS)(nil)
+	//_ fuse.FileSystemSetcrtime  = (*FS)(nil)
+	//_ fuse.FileSystemSetchgtime = (*FS)(nil)
+)