220163f67d
Add a mutex to guard SetUpAt() and TearDownAt() calls - they should not
run in parallel. There is a race in these calls when there are two pods
using the same volume, one of them is dying and the other one starting.
TearDownAt() checks that a volume is not needed by any pods and detaches the
volume. It does so by counting how many times is the volume mounted
(GetMountRefs() call below).
When SetUpAt() of the starting pod already attached the volume and did not mount
it yet, TearDownAt() of the dying pod will detach it - GetMountRefs() does not
count with this volume.
These two threads run in parallel:
dying pod.TearDownAt("myVolume") starting pod.SetUpAt("myVolume")
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| AttachDisk("myVolume")
refs, err := mount.GetMountRefs() |
Unmount("myDir") |
if refs == 1 { |
| | Mount("myVolume", "myDir")
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| DetachDisk("myVolume") |
| start containers - OOPS! The volume is detached!
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finish the pod cleanup
Also, add some logs to cinder plugin for easier debugging in the future, add
a test and update the fake mounter to know about bind mounts.
127 lines
3.5 KiB
Go
127 lines
3.5 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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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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"sync"
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"github.com/golang/glog"
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)
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// FakeMounter implements mount.Interface for tests.
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type FakeMounter struct {
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MountPoints []MountPoint
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Log []FakeAction
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// Some tests run things in parallel, make sure the mounter does not produce
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// any golang's DATA RACE warnings.
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mutex sync.Mutex
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}
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var _ Interface = &FakeMounter{}
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// Values for FakeAction.Action
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const FakeActionMount = "mount"
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const FakeActionUnmount = "unmount"
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// FakeAction objects are logged every time a fake mount or unmount is called.
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type FakeAction struct {
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Action string // "mount" or "unmount"
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Target string // applies to both mount and unmount actions
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Source string // applies only to "mount" actions
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FSType string // applies only to "mount" actions
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}
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func (f *FakeMounter) ResetLog() {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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f.Log = []FakeAction{}
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}
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func (f *FakeMounter) Mount(source string, target string, fstype string, options []string) error {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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// find 'bind' option
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for _, option := range options {
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if option == "bind" {
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// This is a bind-mount. In order to mimic linux behaviour, we must
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// use the original device of the bind-mount as the real source.
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// E.g. when mounted /dev/sda like this:
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// $ mount /dev/sda /mnt/test
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// $ mount -o bind /mnt/test /mnt/bound
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// then /proc/mount contains:
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// /dev/sda /mnt/test
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// /dev/sda /mnt/bound
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// (and not /mnt/test /mnt/bound)
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// I.e. we must use /dev/sda as source instead of /mnt/test in the
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// bind mount.
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for _, mnt := range f.MountPoints {
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if source == mnt.Path {
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source = mnt.Device
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break
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}
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}
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break
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}
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}
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f.MountPoints = append(f.MountPoints, MountPoint{Device: source, Path: target, Type: fstype})
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glog.V(5).Infof("Fake mounter: mouted %s to %s", source, target)
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f.Log = append(f.Log, FakeAction{Action: FakeActionMount, Target: target, Source: source, FSType: fstype})
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return nil
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}
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func (f *FakeMounter) Unmount(target string) error {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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newMountpoints := []MountPoint{}
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for _, mp := range f.MountPoints {
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if mp.Path == target {
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glog.V(5).Infof("Fake mounter: unmouted %s from %s", mp.Device, target)
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// Don't copy it to newMountpoints
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continue
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}
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newMountpoints = append(newMountpoints, MountPoint{Device: mp.Device, Path: mp.Path, Type: mp.Type})
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}
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f.MountPoints = newMountpoints
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f.Log = append(f.Log, FakeAction{Action: FakeActionUnmount, Target: target})
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return nil
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}
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func (f *FakeMounter) List() ([]MountPoint, error) {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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return f.MountPoints, nil
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}
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func (f *FakeMounter) IsLikelyNotMountPoint(file string) (bool, error) {
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f.mutex.Lock()
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defer f.mutex.Unlock()
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for _, mp := range f.MountPoints {
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if mp.Path == file {
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glog.V(5).Infof("isLikelyMountPoint for %s: monted %s, false", file, mp.Path)
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return false, nil
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}
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}
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glog.V(5).Infof("isLikelyMountPoint for %s: true", file)
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return true, nil
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}
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