Enforce zero plugin refcount during disable.

When plugins have a positive refcount, they were not allowed to be
removed. However, plugins could still be disabled when volumes
referenced it and containers using them were running.

This change fixes that by enforcing plugin refcount during disable.
A "force" disable option is also added to ignore reference refcounting.

Signed-off-by: Anusha Ragunathan <anusha@docker.com>

interface.go

@@ -110,7 +110,7 @@ type PluginAPIClient interface {
 	PluginList(ctx context.Context) (types.PluginsListResponse, error)
 	PluginRemove(ctx context.Context, name string, options types.PluginRemoveOptions) error
 	PluginEnable(ctx context.Context, name string, options types.PluginEnableOptions) error
-	PluginDisable(ctx context.Context, name string) error
+	PluginDisable(ctx context.Context, name string, options types.PluginDisableOptions) error
 	PluginInstall(ctx context.Context, name string, options types.PluginInstallOptions) error
 	PluginPush(ctx context.Context, name string, registryAuth string) error
 	PluginSet(ctx context.Context, name string, args []string) error

plugin_disable.go

@@ -1,12 +1,19 @@
 package client
 
 import (
+	"net/url"
+
+	"github.com/docker/docker/api/types"
 	"golang.org/x/net/context"
 )
 
 // PluginDisable disables a plugin
-func (cli *Client) PluginDisable(ctx context.Context, name string) error {
-	resp, err := cli.post(ctx, "/plugins/"+name+"/disable", nil, nil, nil)
+func (cli *Client) PluginDisable(ctx context.Context, name string, options types.PluginDisableOptions) error {
+	query := url.Values{}
+	if options.Force {
+		query.Set("force", "1")
+	}
+	resp, err := cli.post(ctx, "/plugins/"+name+"/disable", query, nil, nil)
 	ensureReaderClosed(resp)
 	return err
 }

plugin_disable_test.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/docker/docker/api/types"
 	"golang.org/x/net/context"
 )
 
@@ -16,7 +17,7 @@ func TestPluginDisableError(t *testing.T) {
 		client: newMockClient(errorMock(http.StatusInternalServerError, "Server error")),
 	}
 
-	err := client.PluginDisable(context.Background(), "plugin_name")
+	err := client.PluginDisable(context.Background(), "plugin_name", types.PluginDisableOptions{})
 	if err == nil || err.Error() != "Error response from daemon: Server error" {
 		t.Fatalf("expected a Server Error, got %v", err)
 	}
@@ -40,7 +41,7 @@ func TestPluginDisable(t *testing.T) {
 		}),
 	}
 
-	err := client.PluginDisable(context.Background(), "plugin_name")
+	err := client.PluginDisable(context.Background(), "plugin_name", types.PluginDisableOptions{})
 	if err != nil {
 		t.Fatal(err)
 	}