diff --git a/cmd/cmount/fs.go b/cmd/cmount/fs.go
index c9242e0cb..f155399ad 100644
--- a/cmd/cmount/fs.go
+++ b/cmd/cmount/fs.go
@@ -540,6 +540,8 @@ func translateError(err error) (errc int) {
 		return -fuse.EROFS
 	case vfs.ENOSYS:
 		return -fuse.ENOSYS
+	case vfs.EINVAL:
+		return -fuse.EINVAL
 	}
 	fs.Errorf(nil, "IO error: %v", err)
 	return -fuse.EIO
diff --git a/cmd/mount/fs.go b/cmd/mount/fs.go
index b892681d4..d8adb35b1 100644
--- a/cmd/mount/fs.go
+++ b/cmd/mount/fs.go
@@ -91,6 +91,8 @@ func translateError(err error) error {
 		return fuse.Errno(syscall.EROFS)
 	case vfs.ENOSYS:
 		return fuse.ENOSYS
+	case vfs.EINVAL:
+		return fuse.Errno(syscall.EINVAL)
 	}
 	return err
 }
diff --git a/vfs/errors.go b/vfs/errors.go
index ac00ca9ad..564671a43 100644
--- a/vfs/errors.go
+++ b/vfs/errors.go
@@ -27,6 +27,7 @@ var (
 	ENOENT = os.ErrNotExist
 	EEXIST = os.ErrExist
 	EPERM  = os.ErrPermission
+	EINVAL = os.ErrInvalid
 	// ECLOSED see errors_{old,new}.go
 )
 
diff --git a/vfs/file.go b/vfs/file.go
index a50abad1f..e44a0e512 100644
--- a/vfs/file.go
+++ b/vfs/file.go
@@ -292,7 +292,6 @@ func (f *File) openRead() (fh *ReadFileHandle, err error) {
 
 	fh, err = newReadFileHandle(f, o)
 	if err != nil {
-		err = errors.Wrap(err, "open for read")
 		fs.Errorf(f, "File.openRead failed: %v", err)
 		return nil, err
 	}
@@ -308,7 +307,6 @@ func (f *File) openWrite(flags int) (fh *WriteFileHandle, err error) {
 
 	fh, err = newWriteFileHandle(f.d, f, f.Path(), flags)
 	if err != nil {
-		err = errors.Wrap(err, "open for write")
 		fs.Errorf(f, "File.openWrite failed: %v", err)
 		return nil, err
 	}
@@ -327,7 +325,6 @@ func (f *File) openRW(flags int) (fh *RWFileHandle, err error) {
 
 	fh, err = newRWFileHandle(f.d, f, f.Path(), flags)
 	if err != nil {
-		err = errors.Wrap(err, "open for read write")
 		fs.Errorf(f, "File.openRW failed: %v", err)
 		return nil, err
 	}
@@ -400,9 +397,16 @@ func (f *File) Open(flags int) (fd Handle, err error) {
 	var (
 		write    bool // if set need write support
 		read     bool // if set need read support
-		rdwrMode = flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR)
+		rdwrMode = flags & accessModeMask
 	)
 
+	// http://pubs.opengroup.org/onlinepubs/7908799/xsh/open.html
+	// The result of using O_TRUNC with O_RDONLY is undefined.
+	// Linux seems to truncate the file, but we prefer to return EINVAL
+	if rdwrMode == os.O_RDONLY && flags&os.O_TRUNC != 0 {
+		return nil, EINVAL
+	}
+
 	// Figure out the read/write intents
 	switch {
 	case rdwrMode == os.O_RDONLY:
diff --git a/vfs/open_test.go b/vfs/open_test.go
index 6ff4b65e6..22f661606 100644
--- a/vfs/open_test.go
+++ b/vfs/open_test.go
@@ -36,13 +36,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_SYNC",
@@ -56,13 +56,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_EXCL,
 		what:                "os.O_RDONLY|os.O_EXCL",
@@ -76,13 +76,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_EXCL | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_EXCL|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_EXCL | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_EXCL|os.O_SYNC",
@@ -96,13 +96,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_EXCL | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_EXCL|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE,
 		what:                "os.O_RDONLY|os.O_CREATE",
@@ -116,13 +116,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_SYNC",
@@ -136,13 +136,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_EXCL,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_EXCL",
@@ -156,10 +156,10 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_EXCL | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_EXCL|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     EEXIST,
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
 		readExistingErr:     nil,
 		writeExistingErr:    nil,
 		contents:            "hello",
@@ -176,10 +176,10 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_CREATE | os.O_EXCL | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_CREATE|os.O_EXCL|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     EEXIST,
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
 		readExistingErr:     nil,
 		writeExistingErr:    nil,
 		contents:            "hello",
@@ -196,13 +196,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_SYNC",
@@ -216,13 +216,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_EXCL,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_EXCL",
@@ -236,13 +236,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_EXCL | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_EXCL|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_EXCL | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_EXCL|os.O_SYNC",
@@ -256,13 +256,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_EXCL | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_EXCL|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  ENOENT,
+		openNonExistentErr:  EINVAL,
 		readNonExistentErr:  nil,
 		writeNonExistentErr: nil,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE",
@@ -276,13 +276,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_SYNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_SYNC",
@@ -296,13 +296,13 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     nil,
-		readExistingErr:     io.EOF,
-		writeExistingErr:    EBADF,
-		contents:            "",
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
+		readExistingErr:     nil,
+		writeExistingErr:    nil,
+		contents:            "hello",
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_EXCL,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_EXCL",
@@ -316,10 +316,10 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_EXCL | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_EXCL|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     EEXIST,
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
 		readExistingErr:     nil,
 		writeExistingErr:    nil,
 		contents:            "hello",
@@ -336,10 +336,10 @@ var openTests = []openTest{
 	}, {
 		flags:               os.O_RDONLY | os.O_APPEND | os.O_CREATE | os.O_EXCL | os.O_SYNC | os.O_TRUNC,
 		what:                "os.O_RDONLY|os.O_APPEND|os.O_CREATE|os.O_EXCL|os.O_SYNC|os.O_TRUNC",
-		openNonExistentErr:  nil,
-		readNonExistentErr:  io.EOF,
-		writeNonExistentErr: EBADF,
-		openExistingErr:     EEXIST,
+		openNonExistentErr:  EINVAL,
+		readNonExistentErr:  nil,
+		writeNonExistentErr: nil,
+		openExistingErr:     EINVAL,
 		readExistingErr:     nil,
 		writeExistingErr:    nil,
 		contents:            "hello",
diff --git a/vfs/read_write_test.go b/vfs/read_write_test.go
index 78acc332e..e0022d676 100644
--- a/vfs/read_write_test.go
+++ b/vfs/read_write_test.go
@@ -523,8 +523,10 @@ func testRWFileHandleOpenTest(t *testing.T, vfs *VFS, test *openTest) {
 	require.NoError(t, err, test.what)
 
 	// check
+	assert.Equal(t, test.openNonExistentErr, openNonExistentErr, "openNonExistentErr: %s: want=%v, got=%v", test.what, test.openNonExistentErr, openNonExistentErr)
 	assert.Equal(t, test.readNonExistentErr, readNonExistentErr, "readNonExistentErr: %s: want=%v, got=%v", test.what, test.readNonExistentErr, readNonExistentErr)
 	assert.Equal(t, test.writeNonExistentErr, writeNonExistentErr, "writeNonExistentErr: %s: want=%v, got=%v", test.what, test.writeNonExistentErr, writeNonExistentErr)
+	assert.Equal(t, test.openExistingErr, openExistingErr, "openExistingErr: %s: want=%v, got=%v", test.what, test.openExistingErr, openExistingErr)
 	assert.Equal(t, test.readExistingErr, readExistingErr, "readExistingErr: %s: want=%v, got=%v", test.what, test.readExistingErr, readExistingErr)
 	assert.Equal(t, test.writeExistingErr, writeExistingErr, "writeExistingErr: %s: want=%v, got=%v", test.what, test.writeExistingErr, writeExistingErr)
 	assert.Equal(t, test.contents, contents, test.what)
diff --git a/vfs/vfs.go b/vfs/vfs.go
index 6726a637c..26a0b11b9 100644
--- a/vfs/vfs.go
+++ b/vfs/vfs.go
@@ -393,6 +393,14 @@ func decodeOpenFlags(flags int) string {
 // OpenFile a file according to the flags and perm provided
 func (vfs *VFS) OpenFile(name string, flags int, perm os.FileMode) (fd Handle, err error) {
 	defer log.Trace(name, "flags=%s, perm=%v", decodeOpenFlags(flags), perm)("fd=%v, err=%v", &fd, &err)
+
+	// http://pubs.opengroup.org/onlinepubs/7908799/xsh/open.html
+	// The result of using O_TRUNC with O_RDONLY is undefined.
+	// Linux seems to truncate the file, but we prefer to return EINVAL
+	if flags&accessModeMask == os.O_RDONLY && flags&os.O_TRUNC != 0 {
+		return nil, EINVAL
+	}
+
 	node, err := vfs.Stat(name)
 	if err != nil {
 		if err != ENOENT || flags&os.O_CREATE == 0 {