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Merge pull request #10658 from darwin-containers/reorganize-mount-unmount

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Reorganize mount/unmount code so it is easier to add Darwin-specific implementation
This commit is contained in:
Akihiro Suda
2024-09-03 01:51:24 +00:00
committed by GitHub
parent 58aa92d1c1 bfc1465a2c
commit cae19b14f3
13 changed files with 200 additions and 221 deletions
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50
core/mount/fuse_linux.go Normal file
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@@ -0,0 +1,50 @@
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package mount
import (
"os/exec"
"golang.org/x/sys/unix"
)
// fuseSuperMagic is defined in statfs(2)
const fuseSuperMagic = 0x65735546
func isFUSE(dir string) bool {
var st unix.Statfs_t
if err := unix.Statfs(dir, &st); err != nil {
return false
}
return st.Type == fuseSuperMagic
}
// unmountFUSE attempts to unmount using fusermount/fusermount3 helper binary.
//
// For FUSE mounts, using these helper binaries is preferred, see:
// https://github.com/containerd/containerd/pull/3765#discussion_r342083514
func unmountFUSE(target string) error {
var err error
for _, helperBinary := range []string{"fusermount3", "fusermount"} {
cmd := exec.Command(helperBinary, "-u", target)
err = cmd.Run()
if err == nil {
return nil
}
}
return err
}

30
core/mount/fuse_unsupported.go Normal file
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@@ -0,0 +1,30 @@
//go:build !linux && !windows
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package mount
import "fmt"
func isFUSE(dir string) bool {
return false
}
// unmountFUSE is not implemented on this platform
func unmountFUSE(target string) error {
return fmt.Errorf("FUSE is not supported on this platform")
}

4
core/mount/mount.go
View File

@@ -19,12 +19,16 @@ package mount
import (
"fmt"
"path/filepath"
"runtime"
"strings"
"github.com/containerd/containerd/api/types"
"github.com/containerd/continuity/fs"
)
// HasBindMounts This is a flag to conditionally disable code that relies on working bind-mount support, so such code is easier to find across codebase.
const HasBindMounts = runtime.GOOS != "darwin" && runtime.GOOS != "openbsd"
// Mount is the lingua franca of containerd. A mount represents a
// serialized mount syscall. Components either emit or consume mounts.
type Mount struct {

24
core/mount/mount_darwin.go Normal file
View File

@@ -0,0 +1,24 @@
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package mount
import "github.com/containerd/errdefs"
// Mount to the provided target.
func (m *Mount) mount(target string) error {
return errdefs.ErrNotImplemented
}

61
core/mount/mount_freebsd.go
View File

@@ -19,18 +19,11 @@ package mount
import (
"errors"
"fmt"
"os"
"os/exec"
"time"
"golang.org/x/sys/unix"
)
var (
// ErrNotImplementOnUnix is returned for methods that are not implemented
ErrNotImplementOnUnix = errors.New("not implemented under unix")
)
// Mount to the provided target.
//
// The "syscall" and "golang.org/x/sys/unix" packages do not define a Mount
@@ -77,57 +70,3 @@ func (m *Mount) mount(target string) error {
}
return fmt.Errorf("mount [%v] failed with ECHILD (retried %d times)", args, retriesOnECHILD)
}
// Unmount the provided mount path with the flags
func Unmount(target string, flags int) error {
if err := unmount(target, flags); err != nil && err != unix.EINVAL {
return err
}
return nil
}
func unmount(target string, flags int) error {
for i := 0; i < 50; i++ {
if err := unix.Unmount(target, flags); err != nil {
switch err {
case unix.EBUSY:
time.Sleep(50 * time.Millisecond)
continue
default:
return err
}
}
return nil
}
return fmt.Errorf("failed to unmount target %s: %w", target, unix.EBUSY)
}
// UnmountAll repeatedly unmounts the given mount point until there
// are no mounts remaining (EINVAL is returned by mount), which is
// useful for undoing a stack of mounts on the same mount point.
// UnmountAll all is noop when the first argument is an empty string.
// This is done when the containerd client did not specify any rootfs
// mounts (e.g. because the rootfs is managed outside containerd)
// UnmountAll is noop when the mount path does not exist.
func UnmountAll(mount string, flags int) error {
if mount == "" {
return nil
}
if _, err := os.Stat(mount); os.IsNotExist(err) {
return nil
}
for {
if err := unmount(mount, flags); err != nil {
// EINVAL is returned if the target is not a
// mount point, indicating that we are
// done. It can also indicate a few other
// things (such as invalid flags) which we
// unfortunately end up squelching here too.
if err == unix.EINVAL {
return nil
}
return err
}
}
}

87
core/mount/mount_linux.go
View File

@@ -26,7 +26,6 @@ import (
"runtime"
"strconv"
"strings"
"time"
"github.com/containerd/log"
"github.com/moby/sys/userns"
@@ -274,92 +273,6 @@ func doPrepareIDMappedOverlay(lowerDirs []string, usernsFd int) (tmpLowerDirs []
return tmpLowerDirs, cleanUp, nil
}
// Unmount the provided mount path with the flags
func Unmount(target string, flags int) error {
if err := unmount(target, flags); err != nil && err != unix.EINVAL {
return err
}
return nil
}
// fuseSuperMagic is defined in statfs(2)
const fuseSuperMagic = 0x65735546
func isFUSE(dir string) bool {
var st unix.Statfs_t
if err := unix.Statfs(dir, &st); err != nil {
return false
}
return st.Type == fuseSuperMagic
}
// unmountFUSE attempts to unmount using fusermount/fusermount3 helper binary.
//
// For FUSE mounts, using these helper binaries is preferred, see:
// https://github.com/containerd/containerd/pull/3765#discussion_r342083514
func unmountFUSE(target string) error {
var err error
for _, helperBinary := range []string{"fusermount3", "fusermount"} {
cmd := exec.Command(helperBinary, "-u", target)
err = cmd.Run()
if err == nil {
return nil
}
}
return err
}
func unmount(target string, flags int) error {
if isFUSE(target) {
if err := unmountFUSE(target); err == nil {
return nil
}
}
for i := 0; i < 50; i++ {
if err := unix.Unmount(target, flags); err != nil {
switch err {
case unix.EBUSY:
time.Sleep(50 * time.Millisecond)
continue
default:
return err
}
}
return nil
}
return fmt.Errorf("failed to unmount target %s: %w", target, unix.EBUSY)
}
// UnmountAll repeatedly unmounts the given mount point until there
// are no mounts remaining (EINVAL is returned by mount), which is
// useful for undoing a stack of mounts on the same mount point.
// UnmountAll all is noop when the first argument is an empty string.
// This is done when the containerd client did not specify any rootfs
// mounts (e.g. because the rootfs is managed outside containerd)
// UnmountAll is noop when the mount path does not exist.
func UnmountAll(mount string, flags int) error {
if mount == "" {
return nil
}
if _, err := os.Stat(mount); os.IsNotExist(err) {
return nil
}
for {
if err := unmount(mount, flags); err != nil {
// EINVAL is returned if the target is not a
// mount point, indicating that we are
// done. It can also indicate a few other
// things (such as invalid flags) which we
// unfortunately end up squelching here too.
if err == unix.EINVAL {
return nil
}
return err
}
}
}
// parseMountOptions takes fstab style mount options and parses them for
// use with a standard mount() syscall
func parseMountOptions(options []string) (opt mountOpt) {

66
core/mount/mount_unix.go
View File

@@ -1,4 +1,4 @@
//go:build !windows && !darwin && !openbsd
//go:build !windows && !openbsd
/*
Copyright The containerd Authors.
@@ -19,10 +19,13 @@
package mount
import (
"fmt"
"os"
"sort"
"time"
"github.com/moby/sys/mountinfo"
"golang.org/x/sys/unix"
)
// UnmountRecursive unmounts the target and all mounts underneath, starting
@@ -69,3 +72,64 @@ func UnmountRecursive(target string, flags int) error {
}
return nil
}
func unmount(target string, flags int) error {
if isFUSE(target) {
// TODO: Why error is ignored?
// Shouldn't this just be unconditional "return unmountFUSE(target)"?
if err := unmountFUSE(target); err == nil {
return nil
}
}
for i := 0; i < 50; i++ {
if err := unix.Unmount(target, flags); err != nil {
switch err {
case unix.EBUSY:
time.Sleep(50 * time.Millisecond)
continue
default:
return err
}
}
return nil
}
return fmt.Errorf("failed to unmount target %s: %w", target, unix.EBUSY)
}
// Unmount the provided mount path with the flags
func Unmount(target string, flags int) error {
if err := unmount(target, flags); err != nil && err != unix.EINVAL {
return err
}
return nil
}
// UnmountAll repeatedly unmounts the given mount point until there
// are no mounts remaining (EINVAL is returned by mount), which is
// useful for undoing a stack of mounts on the same mount point.
// UnmountAll all is noop when the first argument is an empty string.
// This is done when the containerd client did not specify any rootfs
// mounts (e.g. because the rootfs is managed outside containerd)
// UnmountAll is noop when the mount path does not exist.
func UnmountAll(mount string, flags int) error {
if mount == "" {
return nil
}
if _, err := os.Stat(mount); os.IsNotExist(err) {
return nil
}
for {
if err := unmount(mount, flags); err != nil {
// EINVAL is returned if the target is not a
// mount point, indicating that we are
// done. It can also indicate a few other
// things (such as invalid flags) which we
// unfortunately end up squelching here too.
if err == unix.EINVAL {
return nil
}
return err
}
}
}

17
core/mount/mount_unsupported.go
View File

@@ -1,4 +1,4 @@
//go:build darwin || openbsd
//go:build openbsd
/*
Copyright The containerd Authors.
@@ -18,29 +18,24 @@
package mount
import "errors"
var (
// ErrNotImplementOnUnix is returned for methods that are not implemented
ErrNotImplementOnUnix = errors.New("not implemented under unix")
)
import "github.com/containerd/errdefs"
// Mount is not implemented on this platform
func (m *Mount) mount(target string) error {
return ErrNotImplementOnUnix
return errdefs.ErrNotImplemented
}
// Unmount is not implemented on this platform
func Unmount(mount string, flags int) error {
return ErrNotImplementOnUnix
return errdefs.ErrNotImplemented
}
// UnmountAll is not implemented on this platform
func UnmountAll(mount string, flags int) error {
return ErrNotImplementOnUnix
return errdefs.ErrNotImplemented
}
// UnmountRecursive is not implemented on this platform
func UnmountRecursive(mount string, flags int) error {
return ErrNotImplementOnUnix
return errdefs.ErrNotImplemented
}

5
core/mount/mount_windows.go
View File

@@ -33,11 +33,6 @@ import (
const sourceStreamName = "containerd.io-source"
var (
// ErrNotImplementOnWindows is returned when an action is not implemented for windows
ErrNotImplementOnWindows = errors.New("not implemented under windows")
)
// Mount to the provided target.
func (m *Mount) mount(target string) (retErr error) {
if m.Type != "windows-layer" {