Merge pull request #27164 from cpuguy83/carry_24205

Fix volume creates blocked by stale cache entries

integration-cli/docker_cli_external_volume_driver_unix_test.go

@@ -17,10 +17,13 @@ import (
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/pkg/integration/checker"
+	"github.com/docker/docker/pkg/stringid"
 	"github.com/docker/docker/volume"
 	"github.com/go-check/check"
 )
 
+const volumePluginName = "test-external-volume-driver"
+
 func init() {
 	check.Suite(&DockerExternalVolumeSuite{
 		ds: &DockerSuite{},
@@ -40,10 +43,9 @@ type eventCounter struct {
 }
 
 type DockerExternalVolumeSuite struct {
-	server *httptest.Server
+	ds *DockerSuite
-	ds     *DockerSuite
+	d  *Daemon
-	d      *Daemon
+	*volumePlugin
-	ec     *eventCounter
 }
 
 func (s *DockerExternalVolumeSuite) SetUpTest(c *check.C) {
@@ -57,8 +59,29 @@ func (s *DockerExternalVolumeSuite) TearDownTest(c *check.C) {
 }
 
 func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
+	s.volumePlugin = newVolumePlugin(c, volumePluginName)
+}
+
+type volumePlugin struct {
+	ec *eventCounter
+	*httptest.Server
+	vols map[string]vol
+}
+
+type vol struct {
+	Name       string
+	Mountpoint string
+	Ninja      bool // hack used to trigger a null volume return on `Get`
+	Status     map[string]interface{}
+}
+
+func (p *volumePlugin) Close() {
+	p.Server.Close()
+}
+
+func newVolumePlugin(c *check.C, name string) *volumePlugin {
 	mux := http.NewServeMux()
-	s.server = httptest.NewServer(mux)
+	s := &volumePlugin{Server: httptest.NewServer(mux), ec: &eventCounter{}, vols: make(map[string]vol)}
 
 	type pluginRequest struct {
 		Name string
@@ -71,14 +94,6 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 		Err        string `json:",omitempty"`
 	}
 
-	type vol struct {
-		Name       string
-		Mountpoint string
-		Ninja      bool // hack used to trigger a null volume return on `Get`
-		Status     map[string]interface{}
-	}
-	var volList []vol
-
 	read := func(b io.ReadCloser) (pluginRequest, error) {
 		defer b.Close()
 		var pr pluginRequest
@@ -115,14 +130,14 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 		}
 		_, isNinja := pr.Opts["ninja"]
 		status := map[string]interface{}{"Hello": "world"}
-		volList = append(volList, vol{Name: pr.Name, Ninja: isNinja, Status: status})
+		s.vols[pr.Name] = vol{Name: pr.Name, Ninja: isNinja, Status: status}
 		send(w, nil)
 	})
 
 	mux.HandleFunc("/VolumeDriver.List", func(w http.ResponseWriter, r *http.Request) {
 		s.ec.lists++
-		vols := []vol{}
+		vols := make([]vol, 0, len(s.vols))
-		for _, v := range volList {
+		for _, v := range s.vols {
 			if v.Ninja {
 				continue
 			}
@@ -139,19 +154,19 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 			return
 		}
 
-		for _, v := range volList {
+		v, exists := s.vols[pr.Name]
-			if v.Name == pr.Name {
+		if !exists {
-				if v.Ninja {
+			send(w, `{"Err": "no such volume"}`)
-					send(w, map[string]vol{})
-					return
-				}
-
-				v.Mountpoint = hostVolumePath(pr.Name)
-				send(w, map[string]vol{"Volume": v})
-				return
-			}
 		}
-		send(w, `{"Err": "no such volume"}`)
+
+		if v.Ninja {
+			send(w, map[string]vol{})
+			return
+		}
+
+		v.Mountpoint = hostVolumePath(pr.Name)
+		send(w, map[string]vol{"Volume": v})
+		return
 	})
 
 	mux.HandleFunc("/VolumeDriver.Remove", func(w http.ResponseWriter, r *http.Request) {
@@ -162,16 +177,17 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 			return
 		}
 
-		for i, v := range volList {
+		v, ok := s.vols[pr.Name]
-			if v.Name == pr.Name {
+		if !ok {
-				if err := os.RemoveAll(hostVolumePath(v.Name)); err != nil {
+			send(w, nil)
-					send(w, &pluginResp{Err: err.Error()})
+			return
-					return
-				}
-				volList = append(volList[:i], volList[i+1:]...)
-				break
-			}
 		}
+
+		if err := os.RemoveAll(hostVolumePath(v.Name)); err != nil {
+			send(w, &pluginResp{Err: err.Error()})
+			return
+		}
+		delete(s.vols, v.Name)
 		send(w, nil)
 	})
 
@@ -202,7 +218,7 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 			return
 		}
 
-		if err := ioutil.WriteFile(filepath.Join(p, "test"), []byte(s.server.URL), 0644); err != nil {
+		if err := ioutil.WriteFile(filepath.Join(p, "test"), []byte(s.Server.URL), 0644); err != nil {
 			send(w, err)
 			return
 		}
@@ -242,12 +258,13 @@ func (s *DockerExternalVolumeSuite) SetUpSuite(c *check.C) {
 	err := os.MkdirAll("/etc/docker/plugins", 0755)
 	c.Assert(err, checker.IsNil)
 
-	err = ioutil.WriteFile("/etc/docker/plugins/test-external-volume-driver.spec", []byte(s.server.URL), 0644)
+	err = ioutil.WriteFile("/etc/docker/plugins/"+name+".spec", []byte(s.Server.URL), 0644)
 	c.Assert(err, checker.IsNil)
+	return s
 }
 
 func (s *DockerExternalVolumeSuite) TearDownSuite(c *check.C) {
-	s.server.Close()
+	s.volumePlugin.Close()
 
 	err := os.RemoveAll("/etc/docker/plugins")
 	c.Assert(err, checker.IsNil)
@@ -257,9 +274,9 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverNamed(c *check.C) {
 	err := s.d.StartWithBusybox()
 	c.Assert(err, checker.IsNil)
 
-	out, err := s.d.Cmd("run", "--rm", "--name", "test-data", "-v", "external-volume-test:/tmp/external-volume-test", "--volume-driver", "test-external-volume-driver", "busybox:latest", "cat", "/tmp/external-volume-test/test")
+	out, err := s.d.Cmd("run", "--rm", "--name", "test-data", "-v", "external-volume-test:/tmp/external-volume-test", "--volume-driver", volumePluginName, "busybox:latest", "cat", "/tmp/external-volume-test/test")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
-	c.Assert(out, checker.Contains, s.server.URL)
+	c.Assert(out, checker.Contains, s.Server.URL)
 
 	_, err = s.d.Cmd("volume", "rm", "external-volume-test")
 	c.Assert(err, checker.IsNil)
@@ -280,9 +297,9 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverUnnamed(c *check.C)
 	err := s.d.StartWithBusybox()
 	c.Assert(err, checker.IsNil)
 
-	out, err := s.d.Cmd("run", "--rm", "--name", "test-data", "-v", "/tmp/external-volume-test", "--volume-driver", "test-external-volume-driver", "busybox:latest", "cat", "/tmp/external-volume-test/test")
+	out, err := s.d.Cmd("run", "--rm", "--name", "test-data", "-v", "/tmp/external-volume-test", "--volume-driver", volumePluginName, "busybox:latest", "cat", "/tmp/external-volume-test/test")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
-	c.Assert(out, checker.Contains, s.server.URL)
+	c.Assert(out, checker.Contains, s.Server.URL)
 
 	c.Assert(s.ec.activations, checker.Equals, 1)
 	c.Assert(s.ec.creations, checker.Equals, 1)
@@ -295,7 +312,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverVolumesFrom(c *check
 	err := s.d.StartWithBusybox()
 	c.Assert(err, checker.IsNil)
 
-	out, err := s.d.Cmd("run", "--name", "vol-test1", "-v", "/foo", "--volume-driver", "test-external-volume-driver", "busybox:latest")
+	out, err := s.d.Cmd("run", "--name", "vol-test1", "-v", "/foo", "--volume-driver", volumePluginName, "busybox:latest")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
 
 	out, err = s.d.Cmd("run", "--rm", "--volumes-from", "vol-test1", "--name", "vol-test2", "busybox", "ls", "/tmp")
@@ -315,7 +332,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverDeleteContainer(c *c
 	err := s.d.StartWithBusybox()
 	c.Assert(err, checker.IsNil)
 
-	out, err := s.d.Cmd("run", "--name", "vol-test1", "-v", "/foo", "--volume-driver", "test-external-volume-driver", "busybox:latest")
+	out, err := s.d.Cmd("run", "--name", "vol-test1", "-v", "/foo", "--volume-driver", volumePluginName, "busybox:latest")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
 
 	out, err = s.d.Cmd("rm", "-fv", "vol-test1")
@@ -388,7 +405,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverRetryNotImmediatelyE
 		// wait for a retry to occur, then create spec to allow plugin to register
 		time.Sleep(2000 * time.Millisecond)
 		// no need to check for an error here since it will get picked up by the timeout later
-		ioutil.WriteFile(specPath, []byte(s.server.URL), 0644)
+		ioutil.WriteFile(specPath, []byte(s.Server.URL), 0644)
 	}()
 
 	select {
@@ -409,7 +426,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverRetryNotImmediatelyE
 }
 
 func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverBindExternalVolume(c *check.C) {
-	dockerCmd(c, "volume", "create", "-d", "test-external-volume-driver", "foo")
+	dockerCmd(c, "volume", "create", "-d", volumePluginName, "foo")
 	dockerCmd(c, "run", "-d", "--name", "testing", "-v", "foo:/bar", "busybox", "top")
 
 	var mounts []struct {
@@ -420,18 +437,18 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverBindExternalVolume(c
 	c.Assert(json.NewDecoder(strings.NewReader(out)).Decode(&mounts), checker.IsNil)
 	c.Assert(len(mounts), checker.Equals, 1, check.Commentf(out))
 	c.Assert(mounts[0].Name, checker.Equals, "foo")
-	c.Assert(mounts[0].Driver, checker.Equals, "test-external-volume-driver")
+	c.Assert(mounts[0].Driver, checker.Equals, volumePluginName)
 }
 
 func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverList(c *check.C) {
-	dockerCmd(c, "volume", "create", "-d", "test-external-volume-driver", "abc3")
+	dockerCmd(c, "volume", "create", "-d", volumePluginName, "abc3")
 	out, _ := dockerCmd(c, "volume", "ls")
 	ls := strings.Split(strings.TrimSpace(out), "\n")
 	c.Assert(len(ls), check.Equals, 2, check.Commentf("\n%s", out))
 
 	vol := strings.Fields(ls[len(ls)-1])
 	c.Assert(len(vol), check.Equals, 2, check.Commentf("%v", vol))
-	c.Assert(vol[0], check.Equals, "test-external-volume-driver")
+	c.Assert(vol[0], check.Equals, volumePluginName)
 	c.Assert(vol[1], check.Equals, "abc3")
 
 	c.Assert(s.ec.lists, check.Equals, 1)
@@ -440,10 +457,10 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverList(c *check.C) {
 func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverGet(c *check.C) {
 	out, _, err := dockerCmdWithError("volume", "inspect", "dummy")
 	c.Assert(err, check.NotNil, check.Commentf(out))
-	c.Assert(s.ec.gets, check.Equals, 1)
 	c.Assert(out, checker.Contains, "No such volume")
+	c.Assert(s.ec.gets, check.Equals, 1)
 
-	dockerCmd(c, "volume", "create", "test", "-d", "test-external-volume-driver")
+	dockerCmd(c, "volume", "create", "test", "-d", volumePluginName)
 	out, _ = dockerCmd(c, "volume", "inspect", "test")
 
 	type vol struct {
@@ -458,7 +475,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverGet(c *check.C) {
 }
 
 func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverWithDaemonRestart(c *check.C) {
-	dockerCmd(c, "volume", "create", "-d", "test-external-volume-driver", "abc1")
+	dockerCmd(c, "volume", "create", "-d", volumePluginName, "abc1")
 	err := s.d.Restart()
 	c.Assert(err, checker.IsNil)
 
@@ -466,7 +483,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverWithDaemonRestart(c
 	var mounts []types.MountPoint
 	inspectFieldAndMarshall(c, "test", "Mounts", &mounts)
 	c.Assert(mounts, checker.HasLen, 1)
-	c.Assert(mounts[0].Driver, checker.Equals, "test-external-volume-driver")
+	c.Assert(mounts[0].Driver, checker.Equals, volumePluginName)
 }
 
 // Ensures that the daemon handles when the plugin responds to a `Get` request with a null volume and a null error.
@@ -474,7 +491,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverWithDaemonRestart(c
 func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverGetEmptyResponse(c *check.C) {
 	c.Assert(s.d.Start(), checker.IsNil)
 
-	out, err := s.d.Cmd("volume", "create", "-d", "test-external-volume-driver", "abc2", "--opt", "ninja=1")
+	out, err := s.d.Cmd("volume", "create", "-d", volumePluginName, "abc2", "--opt", "ninja=1")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
 
 	out, err = s.d.Cmd("volume", "inspect", "abc2")
@@ -505,7 +522,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverMountID(c *check.C)
 	err := s.d.StartWithBusybox()
 	c.Assert(err, checker.IsNil)
 
-	out, err := s.d.Cmd("run", "--rm", "-v", "external-volume-test:/tmp/external-volume-test", "--volume-driver", "test-external-volume-driver", "busybox:latest", "cat", "/tmp/external-volume-test/test")
+	out, err := s.d.Cmd("run", "--rm", "-v", "external-volume-test:/tmp/external-volume-test", "--volume-driver", volumePluginName, "busybox:latest", "cat", "/tmp/external-volume-test/test")
 	c.Assert(err, checker.IsNil, check.Commentf(out))
 	c.Assert(strings.TrimSpace(out), checker.Not(checker.Equals), "")
 }
@@ -516,7 +533,7 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverCapabilities(c *chec
 	c.Assert(s.ec.caps, checker.Equals, 0)
 
 	for i := 0; i < 3; i++ {
-		out, err := s.d.Cmd("volume", "create", "-d", "test-external-volume-driver", fmt.Sprintf("test%d", i))
+		out, err := s.d.Cmd("volume", "create", "-d", volumePluginName, fmt.Sprintf("test%d", i))
 		c.Assert(err, checker.IsNil, check.Commentf(out))
 		c.Assert(s.ec.caps, checker.Equals, 1)
 		out, err = s.d.Cmd("volume", "inspect", "--format={{.Scope}}", fmt.Sprintf("test%d", i))
@@ -524,3 +541,24 @@ func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverCapabilities(c *chec
 		c.Assert(strings.TrimSpace(out), checker.Equals, volume.GlobalScope)
 	}
 }
+
+func (s *DockerExternalVolumeSuite) TestExternalVolumeDriverOutOfBandDelete(c *check.C) {
+	driverName := stringid.GenerateNonCryptoID()
+	p := newVolumePlugin(c, driverName)
+	defer p.Close()
+
+	c.Assert(s.d.StartWithBusybox(), checker.IsNil)
+
+	out, err := s.d.Cmd("volume", "create", "-d", driverName, "--name", "test")
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+
+	out, err = s.d.Cmd("volume", "create", "-d", "local", "--name", "test")
+	c.Assert(err, checker.NotNil, check.Commentf(out))
+	c.Assert(out, checker.Contains, "volume named test already exists")
+
+	// simulate out of band volume deletion on plugin level
+	delete(p.vols, "test")
+
+	out, err = s.d.Cmd("volume", "create", "-d", "local", "--name", "test")
+	c.Assert(err, checker.IsNil, check.Commentf(out))
+}

volume/store/errors.go

@@ -1,8 +1,9 @@
 package store
 
 import (
-	"errors"
 	"strings"
+
+	"github.com/pkg/errors"
 )
 
 var (
@@ -64,11 +65,12 @@ func IsNameConflict(err error) bool {
 }
 
 func isErr(err error, expected error) bool {
+	err = errors.Cause(err)
 	switch pe := err.(type) {
 	case nil:
 		return false
 	case *OpErr:
-		err = pe.Err
+		err = errors.Cause(pe.Err)
 	}
 	return err == expected
 }

volume/store/store.go

@@ -3,6 +3,7 @@ package store
 import (
 	"bytes"
 	"encoding/json"
+	"net"
 	"os"
 	"path/filepath"
 	"sync"
@@ -117,6 +118,15 @@ func (s *VolumeStore) setNamed(v volume.Volume, ref string) {
 	s.globalLock.Unlock()
 }
 
+// getRefs gets the list of refs for a given name
+// Callers of this function are expected to hold the name lock.
+func (s *VolumeStore) getRefs(name string) []string {
+	s.globalLock.Lock()
+	refs := s.refs[name]
+	s.globalLock.Unlock()
+	return refs
+}
+
 // Purge allows the cleanup of internal data on docker in case
 // the internal data is out of sync with volumes driver plugins.
 func (s *VolumeStore) Purge(name string) {
@@ -251,9 +261,77 @@ func (s *VolumeStore) Create(name, driverName string, opts, labels map[string]st
 	return s.CreateWithRef(name, driverName, "", opts, labels)
 }
 
+// checkConflict checks the local cache for name collisions with the passed in name,
+// for existing volumes with the same name but in a different driver.
+// This is used by `Create` as a best effort to prevent name collisions for volumes.
+// If a matching volume is found that is not a conflict that is returned so the caller
+// does not need to perform an additional lookup.
+// When no matching volume is found, both returns will be nil
+//
+// Note: This does not probe all the drivers for name collisions because v1 plugins
+// are very slow, particularly if the plugin is down, and cause other issues,
+// particularly around locking the store.
+// TODO(cpuguy83): With v2 plugins this shouldn't be a problem. Could also potentially
+// use a connect timeout for this kind of check to ensure we aren't blocking for a
+// long time.
+func (s *VolumeStore) checkConflict(name, driverName string) (volume.Volume, error) {
+	// check the local cache
+	v, _ := s.getNamed(name)
+	if v != nil {
+		vDriverName := v.DriverName()
+		if driverName != "" && vDriverName != driverName {
+			// we have what looks like a conflict
+			// let's see if there are existing refs to this volume, if so we don't need
+			// to go any further since we can assume the volume is legit.
+			if len(s.getRefs(name)) > 0 {
+				return nil, errors.Wrapf(errNameConflict, "driver '%s' already has volume '%s'", vDriverName, name)
+			}
+
+			// looks like there is a conflict, but nothing is referencing it...
+			// let's check if the found volume ref
+			// is stale by checking with the driver if it still exists
+			vd, err := volumedrivers.GetDriver(vDriverName)
+			if err != nil {
+				// play it safe and return the error
+				// TODO(cpuguy83): maybe when when v2 plugins are ubiquitous, we should
+				// just purge this from the cache
+				return nil, errors.Wrapf(errNameConflict, "found reference to volume '%s' in driver '%s', but got an error while checking the driver: %v", name, vDriverName, err)
+			}
+
+			// now check if it still exists in the driver
+			v2, err := vd.Get(name)
+			err = errors.Cause(err)
+			if err != nil {
+				if _, ok := err.(net.Error); ok {
+					// got some error related to the driver connectivity
+					// play it safe and return the error
+					// TODO(cpuguy83): When when v2 plugins are ubiquitous, maybe we should
+					// just purge this from the cache
+					return nil, errors.Wrapf(errNameConflict, "found reference to volume '%s' in driver '%s', but got an error while checking the driver: %v", name, vDriverName, err)
+				}
+
+				// a driver can return whatever it wants, so let's make sure this is nil
+				if v2 == nil {
+					// purge this reference from the cache
+					s.Purge(name)
+					return nil, nil
+				}
+			}
+			if v2 != nil {
+				return nil, errors.Wrapf(errNameConflict, "driver '%s' already has volume '%s'", vDriverName, name)
+			}
+		}
+		return v, nil
+	}
+
+	return nil, nil
+}
+
 // create asks the given driver to create a volume with the name/opts.
 // If a volume with the name is already known, it will ask the stored driver for the volume.
-// If the passed in driver name does not match the driver name which is stored for the given volume name, an error is returned.
+// If the passed in driver name does not match the driver name which is stored
+//  for the given volume name, an error is returned after checking if the reference is stale.
+// If the reference is stale, it will be purged and this create can continue.
 // It is expected that callers of this function hold any necessary locks.
 func (s *VolumeStore) create(name, driverName string, opts, labels map[string]string) (volume.Volume, error) {
 	// Validate the name in a platform-specific manner
@@ -265,10 +343,11 @@ func (s *VolumeStore) create(name, driverName string, opts, labels map[string]st
 		return nil, &OpErr{Err: errInvalidName, Name: name, Op: "create"}
 	}
 
-	if v, exists := s.getNamed(name); exists {
+	v, err := s.checkConflict(name, driverName)
-		if v.DriverName() != driverName && driverName != "" && driverName != volume.DefaultDriverName {
+	if err != nil {
-			return nil, errNameConflict
+		return nil, err
-		}
+	}
+	if v != nil {
 		return v, nil
 	}
 
@@ -291,7 +370,7 @@ func (s *VolumeStore) create(name, driverName string, opts, labels map[string]st
 	if v, _ := vd.Get(name); v != nil {
 		return v, nil
 	}
-	v, err := vd.Create(name, opts)
+	v, err = vd.Create(name, opts)
 	if err != nil {
 		return nil, err
 	}
@@ -432,7 +511,8 @@ func (s *VolumeStore) Remove(v volume.Volume) error {
 	s.locks.Lock(name)
 	defer s.locks.Unlock(name)
 
-	if refs, exists := s.refs[name]; exists && len(refs) > 0 {
+	refs := s.getRefs(name)
+	if len(refs) > 0 {
 		return &OpErr{Err: errVolumeInUse, Name: v.Name(), Op: "remove", Refs: refs}
 	}
 
@@ -473,13 +553,7 @@ func (s *VolumeStore) Refs(v volume.Volume) []string {
 	s.locks.Lock(v.Name())
 	defer s.locks.Unlock(v.Name())
 
-	s.globalLock.Lock()
+	refs := s.getRefs(v.Name())
-	defer s.globalLock.Unlock()
-	refs, exists := s.refs[v.Name()]
-	if !exists {
-		return nil
-	}
-
 	refsOut := make([]string, len(refs))
 	copy(refsOut, refs)
 	return refsOut
@@ -511,7 +585,7 @@ func (s *VolumeStore) FilterByDriver(name string) ([]volume.Volume, error) {
 func (s *VolumeStore) FilterByUsed(vols []volume.Volume, used bool) []volume.Volume {
 	return s.filter(vols, func(v volume.Volume) bool {
 		s.locks.Lock(v.Name())
-		l := len(s.refs[v.Name()])
+		l := len(s.getRefs(v.Name()))
 		s.locks.Unlock(v.Name())
 		if (used && l > 0) || (!used && l == 0) {
 			return true

volume/volume.go

@@ -270,7 +270,6 @@ func ParseMountSpec(cfg mounttypes.Mount, options ...func(*validateOpts)) (*Moun
 		}
 		mp.CopyData = DefaultCopyMode
 
-		mp.Driver = DefaultDriverName
 		if cfg.VolumeOptions != nil {
 			if cfg.VolumeOptions.DriverConfig != nil {
 				mp.Driver = cfg.VolumeOptions.DriverConfig.Name

volume/volume_test.go

@@ -163,8 +163,8 @@ func TestParseMountRawSplit(t *testing.T) {
 			{`name:d::rw`, "local", `d:`, ``, `name`, "local", true, false},
 			{`name:d:`, "local", `d:`, ``, `name`, "local", true, false},
 			// TODO Windows post TP5 - Add readonly support {`name:d::ro`, "local", `d:`, ``, `name`, "local", false, false},
-			{`name:c:`, "", ``, ``, ``, DefaultDriverName, true, true},
+			{`name:c:`, "", ``, ``, ``, "", true, true},
-			{`driver/name:c:`, "", ``, ``, ``, DefaultDriverName, true, true},
+			{`driver/name:c:`, "", ``, ``, ``, "", true, true},
 		}
 	} else {
 		cases = []testParseMountRaw{
@@ -172,10 +172,10 @@ func TestParseMountRawSplit(t *testing.T) {
 			{"/tmp:/tmp2:ro", "", "/tmp2", "/tmp", "", "", false, false},
 			{"/tmp:/tmp3:rw", "", "/tmp3", "/tmp", "", "", true, false},
 			{"/tmp:/tmp4:foo", "", "", "", "", "", false, true},
-			{"name:/named1", "", "/named1", "", "name", DefaultDriverName, true, false},
+			{"name:/named1", "", "/named1", "", "name", "", true, false},
 			{"name:/named2", "external", "/named2", "", "name", "external", true, false},
 			{"name:/named3:ro", "local", "/named3", "", "name", "local", false, false},
-			{"local/name:/tmp:rw", "", "/tmp", "", "local/name", DefaultDriverName, true, false},
+			{"local/name:/tmp:rw", "", "/tmp", "", "local/name", "", true, false},
 			{"/tmp:tmp", "", "", "", "", "", true, true},
 		}
 	}
@@ -207,7 +207,7 @@ func TestParseMountRawSplit(t *testing.T) {
 			t.Fatalf("Expected name '%s', was '%s' for spec '%s'", c.expName, m.Name, c.bind)
 		}
 
-		if (m.Driver != c.expDriver) || (m.Driver == DefaultDriverName && c.expDriver == "") {
+		if m.Driver != c.expDriver {
 			t.Fatalf("Expected driver '%s', was '%s', for spec '%s'", c.expDriver, m.Driver, c.bind)
 		}
 
@@ -233,8 +233,8 @@ func TestParseMountSpec(t *testing.T) {
 		{mount.Mount{Type: mount.TypeBind, Source: testDir, Target: testDestinationPath}, MountPoint{Type: mount.TypeBind, Source: testDir, Destination: testDestinationPath, RW: true}},
 		{mount.Mount{Type: mount.TypeBind, Source: testDir + string(os.PathSeparator), Target: testDestinationPath, ReadOnly: true}, MountPoint{Type: mount.TypeBind, Source: testDir, Destination: testDestinationPath}},
 		{mount.Mount{Type: mount.TypeBind, Source: testDir, Target: testDestinationPath + string(os.PathSeparator), ReadOnly: true}, MountPoint{Type: mount.TypeBind, Source: testDir, Destination: testDestinationPath}},
-		{mount.Mount{Type: mount.TypeVolume, Target: testDestinationPath}, MountPoint{Type: mount.TypeVolume, Destination: testDestinationPath, RW: true, Driver: DefaultDriverName, CopyData: DefaultCopyMode}},
+		{mount.Mount{Type: mount.TypeVolume, Target: testDestinationPath}, MountPoint{Type: mount.TypeVolume, Destination: testDestinationPath, RW: true, CopyData: DefaultCopyMode}},
-		{mount.Mount{Type: mount.TypeVolume, Target: testDestinationPath + string(os.PathSeparator)}, MountPoint{Type: mount.TypeVolume, Destination: testDestinationPath, RW: true, Driver: DefaultDriverName, CopyData: DefaultCopyMode}},
+		{mount.Mount{Type: mount.TypeVolume, Target: testDestinationPath + string(os.PathSeparator)}, MountPoint{Type: mount.TypeVolume, Destination: testDestinationPath, RW: true, CopyData: DefaultCopyMode}},
 	}
 
 	for i, c := range cases {