mirror of
https://github.com/containerd/containerd.git
synced 2026-06-24 08:48:48 +00:00
a5c84021c8
In CI we run make root-test via gotestsum, which executes multiple
package tests concurrently. TestAutoclearTrueLoop attempts to invoke
LOOP_CLR_FD using a device name, which introduces a race condition.
Example race:
Process P1 represents mount.test which runs TestAutoclearTrueLoop
Process P2 represents manager.test which runs TestLoopbackMount
T1: P1 closes fd of loop-device (loop3) (kernel unsets backing-file on close)
T2: P2 gets loop3 from /dev/loop-control
T3: P2 configures loop3 with backing file successfully
T4: P1 invokes removeLoop to clear backing file for loop3
You might see that failure like this
```
=== FAIL: core/mount/manager TestLoopbackMount (0.05s)
log_hook.go:47: time="2025-10-23T21:49:22.532811960Z" level=debug msg="activating mount" func="manager.(*mountManager).Activate" file="/home/runner/work/containerd/containerd/core/mount/manager/manager.go:134" mounts="[{loop /tmp/TestLoopbackMount989607109/001/fs-1621892597 []} {format/ext4 {{ mount 0 }} []}]" name=id1 testcase=TestLoopbackMount
helpers.go💯 unmount /tmp/TestLoopbackMount989607109/001/test-mount-3030342351
manager_linux_test.go:80:
Error Trace: /home/runner/work/containerd/containerd/core/mount/manager/manager_linux_test.go:80
/home/runner/work/containerd/containerd/core/mount/manager/manager_linux_test.go:105
Error: Received unexpected error:
failed to get loop device info: no such device or address
Test: TestLoopbackMount
```
To fix this, the test now compares backing-file's inode directly and does
not call removeLoop when autoclear is set.
Signed-off-by: Wei Fu <fuweid89@gmail.com>
105 lines
2.5 KiB
Go
105 lines
2.5 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 (
|
|
"context"
|
|
"fmt"
|
|
"os"
|
|
"time"
|
|
|
|
"github.com/containerd/errdefs"
|
|
"github.com/containerd/log"
|
|
)
|
|
|
|
func LoopbackHandler() Handler {
|
|
return loopbackHandler{}
|
|
}
|
|
|
|
type loopbackHandler struct {
|
|
}
|
|
|
|
func (loopbackHandler) Mount(ctx context.Context, m Mount, mp string, _ []ActiveMount) (ActiveMount, error) {
|
|
if m.Type != "loop" {
|
|
return ActiveMount{}, errdefs.ErrNotImplemented
|
|
}
|
|
params := LoopParams{
|
|
Autoclear: true,
|
|
}
|
|
// TODO: Handle readonly
|
|
// TODO: Handle direct io
|
|
|
|
t := time.Now()
|
|
loop, err := SetupLoop(m.Source, params)
|
|
if err != nil {
|
|
return ActiveMount{}, err
|
|
}
|
|
defer loop.Close()
|
|
|
|
if err := os.Symlink(loop.Name(), mp); err != nil {
|
|
return ActiveMount{}, err
|
|
}
|
|
|
|
if err := setLoopAutoclear(loop, false); err != nil {
|
|
return ActiveMount{}, err
|
|
}
|
|
|
|
return ActiveMount{
|
|
Mount: m,
|
|
MountedAt: &t,
|
|
MountPoint: mp,
|
|
}, nil
|
|
}
|
|
|
|
func (loopbackHandler) Unmount(ctx context.Context, path string) error {
|
|
loopdev, err := os.Readlink(path)
|
|
if err != nil {
|
|
if os.IsNotExist(err) {
|
|
return nil
|
|
}
|
|
return err
|
|
}
|
|
loop, err := os.Open(loopdev)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer loop.Close()
|
|
|
|
if err := setLoopAutoclear(loop, true); err != nil {
|
|
return fmt.Errorf("failed to set auto clear on loop device %q: %w", loopdev, err)
|
|
}
|
|
|
|
if err := os.Remove(path); err != nil {
|
|
if os.IsNotExist(err) {
|
|
return nil
|
|
}
|
|
|
|
// if removal of the symlink has failed, its possible for the loop device to get cleaned
|
|
// up and re-used. Leave the loop device around to prevent re-use and let a retry of
|
|
// Unmount clear it.`
|
|
if err := setLoopAutoclear(loop, false); err != nil {
|
|
// Very unlikely but log to track in case there is a problem with
|
|
// the loop being cleared and re-used.
|
|
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)
|
|
}
|
|
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|