Ensure SizeRw is shown when a user does 'inspect --size -t container'.

libpod/container_inspect.go

@@ -118,7 +118,7 @@ type InspectContainerData struct {
 	BoundingCaps    []string                    `json:"BoundingCaps"`
 	ExecIDs         []string                    `json:"ExecIDs"`
 	GraphDriver     *driver.Data                `json:"GraphDriver"`
-	SizeRw          int64                       `json:"SizeRw,omitempty"`
+	SizeRw          *int64                      `json:"SizeRw,omitempty"`
 	SizeRootFs      int64                       `json:"SizeRootFs,omitempty"`
 	Mounts          []InspectMount              `json:"Mounts"`
 	Dependencies    []string                    `json:"Dependencies"`
@@ -809,12 +809,13 @@ func (c *Container) getContainerInspectData(size bool, driverData *driver.Data)
 		if err != nil {
 			logrus.Errorf("error getting rootfs size %q: %v", config.ID, err)
 		}
+		data.SizeRootFs = rootFsSize
+
 		rwSize, err := c.rwSize()
 		if err != nil {
 			logrus.Errorf("error getting rw size %q: %v", config.ID, err)
 		}
-		data.SizeRootFs = rootFsSize
-		data.SizeRw = rwSize
+		data.SizeRw = &rwSize
 	}
 	return data, nil
 }

libpod/container_internal.go

@@ -84,7 +84,7 @@ func (c *Container) rootFsSize() (int64, error) {
 	return size + layerSize, err
 }
 
-// rwSize Gets the size of the mutable top layer of the container.
+// rwSize gets the size of the mutable top layer of the container.
 func (c *Container) rwSize() (int64, error) {
 	if c.config.Rootfs != "" {
 		var size int64
@@ -103,14 +103,16 @@ func (c *Container) rwSize() (int64, error) {
 		return 0, err
 	}
 
-	// Get the size of the top layer by calculating the size of the diff
-	// between the layer and its parent.  The top layer of a container is
-	// the only RW layer, all others are immutable
-	layer, err := c.runtime.store.Layer(container.LayerID)
+	// The top layer of a container is
+	// the only readable/writeable layer, all others are immutable.
+	rwLayer, err := c.runtime.store.Layer(container.LayerID)
 	if err != nil {
 		return 0, err
 	}
-	return c.runtime.store.DiffSize(layer.Parent, layer.ID)
+
+	// Get the size of the top layer by calculating the size of the diff
+	// between the layer and its parent.
+	return c.runtime.store.DiffSize(rwLayer.Parent, rwLayer.ID)
 }
 
 // bundlePath returns the path to the container's root filesystem - where the OCI spec will be

test/e2e/inspect_test.go

@@ -86,6 +86,7 @@ var _ = Describe("Podman inspect", func() {
 		Expect(result.ExitCode()).To(Equal(0))
 		conData := result.InspectContainerToJSON()
 		Expect(conData[0].SizeRootFs).To(BeNumerically(">", 0))
+		Expect(*conData[0].SizeRw).To(BeNumerically(">=", 0))
 	})
 
 	It("podman inspect container and image", func() {