Merge pull request #33830 from cpuguy83/33799_fix_plugin_mounts_issue

Make plugin removes more resilient to failure

integration-cli/docker_cli_daemon_test.go

@@ -5,6 +5,7 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -25,6 +26,9 @@ import (
 	"crypto/x509"
 
 	"github.com/cloudflare/cfssl/helpers"
+	"github.com/docker/docker/api"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/client"
 	"github.com/docker/docker/integration-cli/checker"
 	"github.com/docker/docker/integration-cli/cli"
 	"github.com/docker/docker/integration-cli/daemon"
@@ -2980,3 +2984,45 @@ func (s *DockerDaemonSuite) TestShmSizeReload(c *check.C) {
 	c.Assert(err, check.IsNil, check.Commentf("Output: %s", out))
 	c.Assert(strings.TrimSpace(out), check.Equals, fmt.Sprintf("%v", size))
 }
+
+// TestFailedPluginRemove makes sure that a failed plugin remove does not block
+// the daemon from starting
+func (s *DockerDaemonSuite) TestFailedPluginRemove(c *check.C) {
+	testRequires(c, DaemonIsLinux, IsAmd64, SameHostDaemon)
+	d := daemon.New(c, dockerBinary, dockerdBinary, daemon.Config{})
+	d.Start(c)
+	cli, err := client.NewClient(d.Sock(), api.DefaultVersion, nil, nil)
+	c.Assert(err, checker.IsNil)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 300*time.Second)
+	defer cancel()
+
+	name := "test-plugin-rm-fail"
+	out, err := cli.PluginInstall(ctx, name, types.PluginInstallOptions{
+		Disabled:             true,
+		AcceptAllPermissions: true,
+		RemoteRef:            "cpuguy83/docker-logdriver-test",
+	})
+	c.Assert(err, checker.IsNil)
+	defer out.Close()
+	io.Copy(ioutil.Discard, out)
+
+	ctx, cancel = context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	p, _, err := cli.PluginInspectWithRaw(ctx, name)
+	c.Assert(err, checker.IsNil)
+
+	// simulate a bad/partial removal by removing the plugin config.
+	configPath := filepath.Join(d.Root, "plugins", p.ID, "config.json")
+	c.Assert(os.Remove(configPath), checker.IsNil)
+
+	d.Restart(c)
+	ctx, cancel = context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	_, err = cli.Ping(ctx)
+	c.Assert(err, checker.IsNil)
+
+	_, _, err = cli.PluginInspectWithRaw(ctx, name)
+	// plugin should be gone since the config.json is gone
+	c.Assert(err, checker.NotNil)
+}

plugin/backend_linux.go

@@ -13,7 +13,6 @@ import (
 	"os"
 	"path"
 	"path/filepath"
-	"sort"
 	"strings"
 
 	"github.com/Sirupsen/logrus"
@@ -32,6 +31,7 @@ import (
 	"github.com/docker/docker/pkg/mount"
 	"github.com/docker/docker/pkg/pools"
 	"github.com/docker/docker/pkg/progress"
+	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/plugin/v2"
 	refstore "github.com/docker/docker/reference"
 	"github.com/opencontainers/go-digest"
@@ -624,14 +624,20 @@ func (pm *Manager) Remove(name string, config *types.PluginRmConfig) error {
 	}()
 
 	id := p.GetID()
-	pm.config.Store.Remove(p)
 	pluginDir := filepath.Join(pm.config.Root, id)
-	if err := recursiveUnmount(pluginDir); err != nil {
-		logrus.WithField("dir", pluginDir).WithField("id", id).Warn(err)
+
+	if err := mount.RecursiveUnmount(pluginDir); err != nil {
+		return errors.Wrap(err, "error unmounting plugin data")
 	}
-	if err := os.RemoveAll(pluginDir); err != nil {
-		logrus.Warnf("unable to remove %q from plugin remove: %v", pluginDir, err)
+
+	if err := os.Rename(pluginDir, pluginDir+"-removing"); err != nil {
+		return errors.Wrap(err, "error performing atomic remove of plugin dir")
 	}
+
+	if err := system.EnsureRemoveAll(pluginDir); err != nil {
+		return errors.Wrap(err, "error removing plugin dir")
+	}
+	pm.config.Store.Remove(p)
 	pm.config.LogPluginEvent(id, name, "remove")
 	return nil
 }
@@ -652,27 +658,6 @@ func getMounts(root string) ([]string, error) {
 	return mounts, nil
 }
 
-func recursiveUnmount(root string) error {
-	mounts, err := getMounts(root)
-	if err != nil {
-		return err
-	}
-
-	// sort in reverse-lexicographic order so the root mount will always be last
-	sort.Sort(sort.Reverse(sort.StringSlice(mounts)))
-
-	for i, m := range mounts {
-		if err := mount.Unmount(m); err != nil {
-			if i == len(mounts)-1 {
-				return errors.Wrapf(err, "error performing recursive unmount on %s", root)
-			}
-			logrus.WithError(err).WithField("mountpoint", m).Warn("could not unmount")
-		}
-	}
-
-	return nil
-}
-
 // Set sets plugin args
 func (pm *Manager) Set(name string, args []string) error {
 	p, err := pm.config.Store.GetV2Plugin(name)

plugin/manager.go

@@ -163,6 +163,19 @@ func (pm *Manager) StateChanged(id string, e libcontainerd.StateInfo) error {
 	return nil
 }
 
+func handleLoadError(err error, id string) {
+	if err == nil {
+		return
+	}
+	logger := logrus.WithError(err).WithField("id", id)
+	if os.IsNotExist(errors.Cause(err)) {
+		// Likely some error while removing on an older version of docker
+		logger.Warn("missing plugin config, skipping: this may be caused due to a failed remove and requires manual cleanup.")
+		return
+	}
+	logger.Error("error loading plugin, skipping")
+}
+
 func (pm *Manager) reload() error { // todo: restore
 	dir, err := ioutil.ReadDir(pm.config.Root)
 	if err != nil {
@@ -173,9 +186,17 @@ func (pm *Manager) reload() error { // todo: restore
 		if validFullID.MatchString(v.Name()) {
 			p, err := pm.loadPlugin(v.Name())
 			if err != nil {
-				return err
+				handleLoadError(err, v.Name())
+				continue
 			}
 			plugins[p.GetID()] = p
+		} else {
+			if validFullID.MatchString(strings.TrimSuffix(v.Name(), "-removing")) {
+				// There was likely some error while removing this plugin, let's try to remove again here
+				if err := system.EnsureRemoveAll(v.Name()); err != nil {
+					logrus.WithError(err).WithField("id", v.Name()).Warn("error while attempting to clean up previously removed plugin")
+				}
+			}
 		}
 	}
 

plugin/manager_linux.go

@@ -204,7 +204,7 @@ func (pm *Manager) upgradePlugin(p *v2.Plugin, configDigest digest.Digest, blobs
 	// Make sure nothing is mounted
 	// This could happen if the plugin was disabled with `-f` with active mounts.
 	// If there is anything in `orig` is still mounted, this should error out.
-	if err := recursiveUnmount(orig); err != nil {
+	if err := mount.RecursiveUnmount(orig); err != nil {
 		return err
 	}