diff --git a/vendor/golang.org/x/sys/unix/fstatfs_zos.go b/vendor/golang.org/x/sys/unix/fstatfs_zos.go
new file mode 100644
index 0000000..e377cc9
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/fstatfs_zos.go
@@ -0,0 +1,164 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build zos && s390x
+// +build zos,s390x
+
+package unix
+
+import (
+	"unsafe"
+)
+
+// This file simulates fstatfs on z/OS using fstatvfs and w_getmntent.
+
+func Fstatfs(fd int, stat *Statfs_t) (err error) {
+	var stat_v Statvfs_t
+	err = Fstatvfs(fd, &stat_v)
+	if err == nil {
+		// populate stat
+		stat.Type = 0
+		stat.Bsize = stat_v.Bsize
+		stat.Blocks = stat_v.Blocks
+		stat.Bfree = stat_v.Bfree
+		stat.Bavail = stat_v.Bavail
+		stat.Files = stat_v.Files
+		stat.Ffree = stat_v.Ffree
+		stat.Fsid = stat_v.Fsid
+		stat.Namelen = stat_v.Namemax
+		stat.Frsize = stat_v.Frsize
+		stat.Flags = stat_v.Flag
+		for passn := 0; passn < 5; passn++ {
+			switch passn {
+			case 0:
+				err = tryGetmntent64(stat)
+				break
+			case 1:
+				err = tryGetmntent128(stat)
+				break
+			case 2:
+				err = tryGetmntent256(stat)
+				break
+			case 3:
+				err = tryGetmntent512(stat)
+				break
+			case 4:
+				err = tryGetmntent1024(stat)
+				break
+			default:
+				break
+			}
+			//proceed to return if: err is nil (found), err is nonnil but not ERANGE (another error occurred)
+			if err == nil || err != nil && err != ERANGE {
+				break
+			}
+		}
+	}
+	return err
+}
+
+func tryGetmntent64(stat *Statfs_t) (err error) {
+	var mnt_ent_buffer struct {
+		header       W_Mnth
+		filesys_info [64]W_Mntent
+	}
+	var buffer_size int = int(unsafe.Sizeof(mnt_ent_buffer))
+	fs_count, err := W_Getmntent((*byte)(unsafe.Pointer(&mnt_ent_buffer)), buffer_size)
+	if err != nil {
+		return err
+	}
+	err = ERANGE //return ERANGE if no match is found in this batch
+	for i := 0; i < fs_count; i++ {
+		if stat.Fsid == uint64(mnt_ent_buffer.filesys_info[i].Dev) {
+			stat.Type = uint32(mnt_ent_buffer.filesys_info[i].Fstname[0])
+			err = nil
+			break
+		}
+	}
+	return err
+}
+
+func tryGetmntent128(stat *Statfs_t) (err error) {
+	var mnt_ent_buffer struct {
+		header       W_Mnth
+		filesys_info [128]W_Mntent
+	}
+	var buffer_size int = int(unsafe.Sizeof(mnt_ent_buffer))
+	fs_count, err := W_Getmntent((*byte)(unsafe.Pointer(&mnt_ent_buffer)), buffer_size)
+	if err != nil {
+		return err
+	}
+	err = ERANGE //return ERANGE if no match is found in this batch
+	for i := 0; i < fs_count; i++ {
+		if stat.Fsid == uint64(mnt_ent_buffer.filesys_info[i].Dev) {
+			stat.Type = uint32(mnt_ent_buffer.filesys_info[i].Fstname[0])
+			err = nil
+			break
+		}
+	}
+	return err
+}
+
+func tryGetmntent256(stat *Statfs_t) (err error) {
+	var mnt_ent_buffer struct {
+		header       W_Mnth
+		filesys_info [256]W_Mntent
+	}
+	var buffer_size int = int(unsafe.Sizeof(mnt_ent_buffer))
+	fs_count, err := W_Getmntent((*byte)(unsafe.Pointer(&mnt_ent_buffer)), buffer_size)
+	if err != nil {
+		return err
+	}
+	err = ERANGE //return ERANGE if no match is found in this batch
+	for i := 0; i < fs_count; i++ {
+		if stat.Fsid == uint64(mnt_ent_buffer.filesys_info[i].Dev) {
+			stat.Type = uint32(mnt_ent_buffer.filesys_info[i].Fstname[0])
+			err = nil
+			break
+		}
+	}
+	return err
+}
+
+func tryGetmntent512(stat *Statfs_t) (err error) {
+	var mnt_ent_buffer struct {
+		header       W_Mnth
+		filesys_info [512]W_Mntent
+	}
+	var buffer_size int = int(unsafe.Sizeof(mnt_ent_buffer))
+	fs_count, err := W_Getmntent((*byte)(unsafe.Pointer(&mnt_ent_buffer)), buffer_size)
+	if err != nil {
+		return err
+	}
+	err = ERANGE //return ERANGE if no match is found in this batch
+	for i := 0; i < fs_count; i++ {
+		if stat.Fsid == uint64(mnt_ent_buffer.filesys_info[i].Dev) {
+			stat.Type = uint32(mnt_ent_buffer.filesys_info[i].Fstname[0])
+			err = nil
+			break
+		}
+	}
+	return err
+}
+
+func tryGetmntent1024(stat *Statfs_t) (err error) {
+	var mnt_ent_buffer struct {
+		header       W_Mnth
+		filesys_info [1024]W_Mntent
+	}
+	var buffer_size int = int(unsafe.Sizeof(mnt_ent_buffer))
+	fs_count, err := W_Getmntent((*byte)(unsafe.Pointer(&mnt_ent_buffer)), buffer_size)
+	if err != nil {
+		return err
+	}
+	err = ERANGE //return ERANGE if no match is found in this batch
+	for i := 0; i < fs_count; i++ {
+		if stat.Fsid == uint64(mnt_ent_buffer.filesys_info[i].Dev) {
+			stat.Type = uint32(mnt_ent_buffer.filesys_info[i].Fstname[0])
+			err = nil
+			break
+		}
+	}
+	return err
+}