cephfs: add file method RemoveXattr implementing ceph_fremovexattr

Add RemoveXattr implementing ceph_fremovexattr as well as a test for it.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

cephfs/file_xattr.go

@@ -138,3 +138,24 @@ func (f *File) ListXattr() ([]string, error) {
 	}
 	return names, nil
 }
+
+// RemoveXattr removes the named xattr from the open file.
+//
+// Implements:
+//  int ceph_fremovexattr(struct ceph_mount_info *cmount, int fd, const char *name);
+func (f *File) RemoveXattr(name string) error {
+	if err := f.validate(); err != nil {
+		return err
+	}
+	if name == "" {
+		return errInvalid
+	}
+	cName := C.CString(name)
+	defer C.free(unsafe.Pointer(cName))
+
+	ret := C.ceph_fremovexattr(
+		f.mount.mount,
+		f.fd,
+		cName)
+	return getError(ret)
+}

cephfs/file_xattr_test.go

@@ -118,3 +118,40 @@ func TestListXattr(t *testing.T) {
 		assert.Error(t, err)
 	})
 }
+
+func TestRemoveXattr(t *testing.T) {
+	mount := fsConnect(t)
+	defer fsDisconnect(t, mount)
+	fname := "TestRemoveXattr.txt"
+
+	f, err := mount.Open(fname, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, f.Close())
+		assert.NoError(t, mount.Unlink(fname))
+	}()
+
+	t.Run("removeXattr", func(t *testing.T) {
+		s := samples[0]
+		err := f.SetXattr(s.name, s.value, XattrDefault)
+		err = f.RemoveXattr(s.name)
+		assert.NoError(t, err)
+	})
+
+	t.Run("removeMissingXattr", func(t *testing.T) {
+		s := samples[1]
+		err := f.RemoveXattr(s.name)
+		assert.Error(t, err)
+	})
+
+	t.Run("emptyName", func(t *testing.T) {
+		err := f.RemoveXattr("")
+		assert.Error(t, err)
+	})
+
+	t.Run("invalidFile", func(t *testing.T) {
+		f1 := &File{}
+		err := f1.RemoveXattr(samples[0].name)
+		assert.Error(t, err)
+	})
+}