127 lines
3.2 KiB
Go
127 lines
3.2 KiB
Go
//go:build !windows && !openbsd
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/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package mount
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import (
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"fmt"
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"os"
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"sort"
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"time"
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"github.com/moby/sys/mountinfo"
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"golang.org/x/sys/unix"
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)
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// UnmountRecursive unmounts the target and all mounts underneath, starting
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// with the deepest mount first.
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func UnmountRecursive(target string, flags int) error {
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if target == "" {
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return nil
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}
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mounts, err := mountinfo.GetMounts(mountinfo.PrefixFilter(target))
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if err != nil {
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return err
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}
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targetSet := make(map[string]struct{})
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for _, m := range mounts {
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targetSet[m.Mountpoint] = struct{}{}
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}
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var targets []string
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for m := range targetSet {
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targets = append(targets, m)
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}
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// Make the deepest mount be first
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sort.SliceStable(targets, func(i, j int) bool {
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return len(targets[i]) > len(targets[j])
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})
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for i, target := range targets {
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if err := UnmountAll(target, flags); err != nil {
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if i == len(targets)-1 { // last mount
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return err
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}
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}
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}
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return nil
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}
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func unmount(target string, flags int) error {
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if isFUSE(target) {
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// TODO: Why error is ignored?
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// Shouldn't this just be "return unmountFUSE(target)"?
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if err := unmountFUSE(target); err == nil {
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return nil
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}
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}
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for i := 0; i < 50; i++ {
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if err := unix.Unmount(target, flags); err != nil {
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switch err {
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case unix.EBUSY:
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time.Sleep(50 * time.Millisecond)
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continue
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default:
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return err
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}
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}
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return nil
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}
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return fmt.Errorf("failed to unmount target %s: %w", target, unix.EBUSY)
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}
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// Unmount the provided mount path with the flags
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func Unmount(target string, flags int) error {
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if err := unmount(target, flags); err != nil && err != unix.EINVAL {
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return err
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}
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return nil
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}
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// UnmountAll repeatedly unmounts the given mount point until there
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// are no mounts remaining (EINVAL is returned by mount), which is
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// useful for undoing a stack of mounts on the same mount point.
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// UnmountAll all is noop when the first argument is an empty string.
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// This is done when the containerd client did not specify any rootfs
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// mounts (e.g. because the rootfs is managed outside containerd)
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// UnmountAll is noop when the mount path does not exist.
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func UnmountAll(mount string, flags int) error {
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if mount == "" {
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return nil
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}
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if _, err := os.Stat(mount); os.IsNotExist(err) {
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return nil
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}
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for {
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if err := unmount(mount, flags); err != nil {
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// EINVAL is returned if the target is not a
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// mount point, indicating that we are
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// done. It can also indicate a few other
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// things (such as invalid flags) which we
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// unfortunately end up squelching here too.
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if err == unix.EINVAL {
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return nil
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}
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return err
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}
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}
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}
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