From 1a17bc6bc4a61bdbca5c840c556039b4660ab74a Mon Sep 17 00:00:00 2001
From: Brian Goff <cpuguy83@gmail.com>
Date: Thu, 2 Feb 2017 23:08:35 -0500
Subject: [PATCH] Make propagated mount persist outside rootfs
This persists the "propagated mount" for plugins outside the main
rootfs. This enables `docker plugin upgrade` to not remove potentially
important data during upgrade rather than forcing plugin authors to hard
code a host path to persist data to.
Also migrates old plugins that have a propagated mount which is in the
rootfs on daemon startup.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit e8307b868de9f19bb97f5cafcd727df5c5f501be)
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
---
docs/extend/config.md | 2 ++
integration-cli/docker_cli_plugins_test.go | 7 +++-
plugin/backend_linux.go | 42 ++++++++++++++++++++++
plugin/manager.go | 25 +++++++++++++
plugin/manager_linux.go | 18 ++++++++--
5 files changed, 91 insertions(+), 3 deletions(-)
diff --git a/docs/extend/config.md b/docs/extend/config.md
index b98be592a0..096d2d0822 100644
--- a/docs/extend/config.md
+++ b/docs/extend/config.md
@@ -114,6 +114,8 @@ Config provides the base accessible fields for working with V0 plugin format
- **`propagatedMount`** *string*
path to be mounted as rshared, so that mounts under that path are visible to docker. This is useful for volume plugins.
+ This path will be bind-mounted outisde of the plugin rootfs so it's contents
+ are preserved on upgrade.
- **`env`** *PluginEnv array*
diff --git a/integration-cli/docker_cli_plugins_test.go b/integration-cli/docker_cli_plugins_test.go
index 6376da78c1..380357d303 100644
--- a/integration-cli/docker_cli_plugins_test.go
+++ b/integration-cli/docker_cli_plugins_test.go
@@ -366,6 +366,9 @@ func (s *DockerSuite) TestPluginUpgrade(c *check.C) {
pluginV2 := "cpuguy83/docker-volume-driver-plugin-local:v2"
dockerCmd(c, "plugin", "install", "--grant-all-permissions", plugin)
+ dockerCmd(c, "volume", "create", "--driver", plugin, "bananas")
+ dockerCmd(c, "run", "--rm", "-v", "bananas:/apple", "busybox", "sh", "-c", "touch /apple/core")
+
out, _, err := dockerCmdWithError("plugin", "upgrade", "--grant-all-permissions", plugin, pluginV2)
c.Assert(err, checker.NotNil, check.Commentf(out))
c.Assert(out, checker.Contains, "disabled before upgrading")
@@ -377,7 +380,7 @@ func (s *DockerSuite) TestPluginUpgrade(c *check.C) {
_, err = os.Stat(filepath.Join(dockerBasePath, "plugins", id, "rootfs", "v2"))
c.Assert(os.IsNotExist(err), checker.True, check.Commentf(out))
- dockerCmd(c, "plugin", "disable", plugin)
+ dockerCmd(c, "plugin", "disable", "-f", plugin)
dockerCmd(c, "plugin", "upgrade", "--grant-all-permissions", "--skip-remote-check", plugin, pluginV2)
// make sure "v2" file exists
@@ -385,4 +388,6 @@ func (s *DockerSuite) TestPluginUpgrade(c *check.C) {
c.Assert(err, checker.IsNil)
dockerCmd(c, "plugin", "enable", plugin)
+ dockerCmd(c, "volume", "inspect", "bananas")
+ dockerCmd(c, "run", "--rm", "-v", "bananas:/apple", "busybox", "sh", "-c", "ls -lh /apple/core")
}
diff --git a/plugin/backend_linux.go b/plugin/backend_linux.go
index 97046ee185..33200d8efa 100644
--- a/plugin/backend_linux.go
+++ b/plugin/backend_linux.go
@@ -13,6 +13,7 @@ import (
"os"
"path"
"path/filepath"
+ "sort"
"strings"
"github.com/Sirupsen/logrus"
@@ -25,6 +26,7 @@ import (
"github.com/docker/docker/image"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/chrootarchive"
+ "github.com/docker/docker/pkg/mount"
"github.com/docker/docker/pkg/pools"
"github.com/docker/docker/pkg/progress"
"github.com/docker/docker/plugin/v2"
@@ -560,6 +562,9 @@ 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(pm.config.Root); err != nil {
+ logrus.WithField("dir", pm.config.Root).WithField("id", id).Warn(err)
+ }
if err := os.RemoveAll(pluginDir); err != nil {
logrus.Warnf("unable to remove %q from plugin remove: %v", pluginDir, err)
}
@@ -567,6 +572,43 @@ func (pm *Manager) Remove(name string, config *types.PluginRmConfig) error {
return nil
}
+func getMounts(root string) ([]string, error) {
+ infos, err := mount.GetMounts()
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to read mount table while performing recursive unmount")
+ }
+
+ var mounts []string
+ for _, m := range infos {
+ if strings.HasPrefix(m.Mountpoint, root) {
+ mounts = append(mounts, m.Mountpoint)
+ }
+ }
+
+ 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)
diff --git a/plugin/manager.go b/plugin/manager.go
index 2598321e60..f260aa61a7 100644
--- a/plugin/manager.go
+++ b/plugin/manager.go
@@ -145,6 +145,10 @@ func (pm *Manager) StateChanged(id string, e libcontainerd.StateInfo) error {
if err := mount.Unmount(p.PropagatedMount); err != nil {
logrus.Warnf("Could not unmount %s: %v", p.PropagatedMount, err)
}
+ propRoot := filepath.Join(filepath.Dir(p.Rootfs), "propagated-mount")
+ if err := mount.Unmount(propRoot); err != nil {
+ logrus.Warn("Could not unmount %s: %v", propRoot, err)
+ }
}
if restart {
@@ -193,6 +197,27 @@ func (pm *Manager) reload() error { // todo: restore
for _, typ := range p.PluginObj.Config.Interface.Types {
if (typ.Capability == "volumedriver" || typ.Capability == "graphdriver") && typ.Prefix == "docker" && strings.HasPrefix(typ.Version, "1.") {
if p.PluginObj.Config.PropagatedMount != "" {
+ propRoot := filepath.Join(filepath.Dir(p.Rootfs), "propagated-mount")
+
+ // check if we need to migrate an older propagated mount from before
+ // these mounts were stored outside the plugin rootfs
+ if _, err := os.Stat(propRoot); os.IsNotExist(err) {
+ if _, err := os.Stat(p.PropagatedMount); err == nil {
+ // make sure nothing is mounted here
+ // don't care about errors
+ mount.Unmount(p.PropagatedMount)
+ if err := os.Rename(p.PropagatedMount, propRoot); err != nil {
+ logrus.WithError(err).WithField("dir", propRoot).Error("error migrating propagated mount storage")
+ }
+ if err := os.MkdirAll(p.PropagatedMount, 0755); err != nil {
+ logrus.WithError(err).WithField("dir", p.PropagatedMount).Error("error migrating propagated mount storage")
+ }
+ }
+ }
+
+ if err := os.MkdirAll(propRoot, 0755); err != nil {
+ logrus.Errorf("failed to create PropagatedMount directory at %s: %v", propRoot, err)
+ }
// TODO: sanitize PropagatedMount and prevent breakout
p.PropagatedMount = filepath.Join(p.Rootfs, p.PluginObj.Config.PropagatedMount)
if err := os.MkdirAll(p.PropagatedMount, 0755); err != nil {
diff --git a/plugin/manager_linux.go b/plugin/manager_linux.go
index f13b43c415..ad66616628 100644
--- a/plugin/manager_linux.go
+++ b/plugin/manager_linux.go
@@ -40,9 +40,20 @@ func (pm *Manager) enable(p *v2.Plugin, c *controller, force bool) error {
pm.cMap[p] = c
pm.mu.Unlock()
+ var propRoot string
if p.PropagatedMount != "" {
- if err := mount.MakeRShared(p.PropagatedMount); err != nil {
- return errors.WithStack(err)
+ propRoot = filepath.Join(filepath.Dir(p.Rootfs), "propagated-mount")
+
+ if err := os.MkdirAll(propRoot, 0755); err != nil {
+ logrus.Errorf("failed to create PropagatedMount directory at %s: %v", propRoot, err)
+ }
+
+ if err := mount.MakeRShared(propRoot); err != nil {
+ return errors.Wrap(err, "error setting up propagated mount dir")
+ }
+
+ if err := mount.Mount(propRoot, p.PropagatedMount, "none", "rbind"); err != nil {
+ return errors.Wrap(err, "error creating mount for propagated mount")
}
}
@@ -55,6 +66,9 @@ func (pm *Manager) enable(p *v2.Plugin, c *controller, force bool) error {
if err := mount.Unmount(p.PropagatedMount); err != nil {
logrus.Warnf("Could not unmount %s: %v", p.PropagatedMount, err)
}
+ if err := mount.Unmount(propRoot); err != nil {
+ logrus.Warnf("Could not unmount %s: %v", propRoot, err)
+ }
}
return errors.WithStack(err)
}