containerd/mount/mount.go
Edgar Lee 34d5878185 Use mount.Target to specify subdirectory of rootfs mount
- Add Target to mount.Mount.
- Add UnmountMounts to unmount a list of mounts in reverse order.
- Add UnmountRecursive to unmount deepest mount first for a given target, using
moby/sys/mountinfo.

Signed-off-by: Edgar Lee <edgarhinshunlee@gmail.com>
2023-01-27 09:51:58 +08:00

78 lines
2.2 KiB
Go

/*
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"
"github.com/containerd/continuity/fs"
)
// Mount is the lingua franca of containerd. A mount represents a
// serialized mount syscall. Components either emit or consume mounts.
type Mount struct {
// Type specifies the host-specific of the mount.
Type string
// Source specifies where to mount from. Depending on the host system, this
// can be a source path or device.
Source string
// Target specifies an optional subdirectory as a mountpoint. It assumes that
// the subdirectory exists in a parent mount.
Target string
// Options contains zero or more fstab-style mount options. Typically,
// these are platform specific.
Options []string
}
// All mounts all the provided mounts to the provided target. If submounts are
// present, it assumes that parent mounts come before child mounts.
func All(mounts []Mount, target string) error {
for _, m := range mounts {
if err := m.Mount(target); err != nil {
return err
}
}
return nil
}
// UnmountMounts unmounts all the mounts under a target in the reverse order of
// the mounts array provided.
func UnmountMounts(mounts []Mount, target string, flags int) error {
for i := len(mounts) - 1; i >= 0; i-- {
mountpoint, err := fs.RootPath(target, mounts[i].Target)
if err != nil {
return err
}
if err := UnmountAll(mountpoint, flags); err != nil {
if i == len(mounts)-1 { // last mount
return err
}
}
}
return nil
}
// Mount to the provided target path.
func (m *Mount) Mount(target string) error {
target, err := fs.RootPath(target, m.Target)
if err != nil {
return fmt.Errorf("failed to join path %q with root %q: %w", m.Target, target, err)
}
return m.mount(target)
}