Restore container configs when update failed

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

daemon/update.go

@@ -45,6 +45,17 @@ func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) erro
 		return err
 	}
 
+	restoreConfig := false
+	backupHostConfig := *container.HostConfig
+	defer func() {
+		if restoreConfig {
+			container.Lock()
+			container.HostConfig = &backupHostConfig
+			container.ToDisk()
+			container.Unlock()
+		}
+	}()
+
 	if container.RemovalInProgress || container.Dead {
 		errMsg := fmt.Errorf("Container is marked for removal and cannot be \"update\".")
 		return derr.ErrorCodeCantUpdate.WithArgs(container.ID, errMsg)
@@ -56,6 +67,7 @@ func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) erro
 	}
 
 	if err := container.UpdateContainer(hostConfig); err != nil {
+		restoreConfig = true
 		return derr.ErrorCodeCantUpdate.WithArgs(container.ID, err.Error())
 	}
 
@@ -73,6 +85,7 @@ func (daemon *Daemon) update(name string, hostConfig *container.HostConfig) erro
 	// to the real world.
 	if container.IsRunning() && !container.IsRestarting() {
 		if err := daemon.execDriver.Update(container.Command); err != nil {
+			restoreConfig = true
 			return derr.ErrorCodeCantUpdate.WithArgs(container.ID, err.Error())
 		}
 	}

integration-cli/docker_cli_update_unix_test.go

@@ -155,6 +155,31 @@ func (s *DockerSuite) TestUpdateSwapMemoryOnly(c *check.C) {
 	c.Assert(strings.TrimSpace(out), checker.Equals, "629145600")
 }
 
+func (s *DockerSuite) TestUpdateInvalidSwapMemory(c *check.C) {
+	testRequires(c, DaemonIsLinux)
+	testRequires(c, memoryLimitSupport)
+	testRequires(c, swapMemorySupport)
+
+	name := "test-update-container"
+	dockerCmd(c, "run", "-d", "--name", name, "--memory", "300M", "--memory-swap", "500M", "busybox", "top")
+	_, _, err := dockerCmdWithError("update", "--memory-swap", "200M", name)
+	// Update invalid swap memory should fail.
+	// This will pass docker config validation, but failed at kernel validation
+	c.Assert(err, check.NotNil)
+
+	// Update invalid swap memory with failure should not change HostConfig
+	c.Assert(inspectField(c, name, "HostConfig.Memory"), checker.Equals, "314572800")
+	c.Assert(inspectField(c, name, "HostConfig.MemorySwap"), checker.Equals, "524288000")
+
+	dockerCmd(c, "update", "--memory-swap", "600M", name)
+
+	c.Assert(inspectField(c, name, "HostConfig.MemorySwap"), checker.Equals, "629145600")
+
+	file := "/sys/fs/cgroup/memory/memory.memsw.limit_in_bytes"
+	out, _ := dockerCmd(c, "exec", name, "cat", file)
+	c.Assert(strings.TrimSpace(out), checker.Equals, "629145600")
+}
+
 func (s *DockerSuite) TestUpdateStats(c *check.C) {
 	testRequires(c, DaemonIsLinux)
 	testRequires(c, memoryLimitSupport)