mirror of
https://github.com/containerd/containerd.git
synced 2026-08-09 17:39:22 +00:00
104 lines
2.4 KiB
Go
104 lines
2.4 KiB
Go
/*
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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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"context"
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"os"
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"time"
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"github.com/containerd/errdefs"
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"github.com/containerd/log"
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)
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func LoopbackHandler() Handler {
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return loopbackHandler{}
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}
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type loopbackHandler struct {
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}
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func (loopbackHandler) Mount(ctx context.Context, m Mount, mp string, _ []ActiveMount) (ActiveMount, error) {
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if m.Type != "loop" {
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return ActiveMount{}, errdefs.ErrNotImplemented
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}
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params := LoopParams{
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Autoclear: true,
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}
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// TODO: Handle readonly
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// TODO: Handle direct io
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t := time.Now()
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loop, err := setupLoop(m.Source, params)
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if err != nil {
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return ActiveMount{}, err
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}
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defer loop.Close()
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if err := os.Symlink(loop.Name(), mp); err != nil {
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return ActiveMount{}, err
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}
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if err := setLoopAutoclear(loop, false); err != nil {
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return ActiveMount{}, err
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}
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return ActiveMount{
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Mount: m,
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MountedAt: &t,
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MountPoint: mp,
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}, nil
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}
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func (loopbackHandler) Unmount(ctx context.Context, path string) error {
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loopdev, err := os.Readlink(path)
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if err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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return err
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}
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loop, err := os.Open(loopdev)
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if err != nil {
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return err
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}
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defer loop.Close()
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if err := setLoopAutoclear(loop, true); err != nil {
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return err
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}
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if err := os.Remove(path); err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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// if removal of the symlink has failed, its possible for the loop device to get cleaned
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// up and re-used. Leave the loop device around to prevent re-use and let a retry of
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// Unmount clear it.`
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if err := setLoopAutoclear(loop, false); err != nil {
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// Very unlikely but log to track in case there is a problem with
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// the loop being cleared and re-used.
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log.G(ctx).WithError(err).Errorf("Failed to unset auto clear flag on symlink removal failure, loopback %q may be cleaned up while still being tracked", loopdev)
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}
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return err
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}
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return nil
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}
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