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ct: give criu informations about cgroup mounts
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Actually cgroup mounts are bind-mounts, so they should be
handled by the same way.

Reported-by: Ross Boucher <rboucher@gmail.com>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
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@avagin
avagin committed Jul 20, 2015
1 parent 1eeb86f commit af4a5e7
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Showing 2 changed files with 83 additions and 40 deletions.
76 changes: 54 additions & 22 deletions libcontainer/container_linux.go
View file
Expand Up @@ -293,6 +293,19 @@ func (c *linuxContainer) checkCriuVersion() error {

const descriptors_filename = "descriptors.json"

func (c *linuxContainer) addCriuDumpMount(req *criurpc.CriuReq, m *configs.Mount) {
mountDest := m.Destination
if strings.HasPrefix(mountDest, c.config.Rootfs) {
mountDest = mountDest[len(c.config.Rootfs):]
}

extMnt := &criurpc.ExtMountMap{
Key: proto.String(mountDest),
Val: proto.String(mountDest),
}
req.Opts.ExtMnt = append(req.Opts.ExtMnt, extMnt)
}

func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
c.m.Lock()
defer c.m.Unlock()
Expand Down Expand Up @@ -356,22 +369,25 @@ func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
}

t := criurpc.CriuReqType_DUMP
req := criurpc.CriuReq{
req := &criurpc.CriuReq{
Type: &t,
Opts: &rpcOpts,
}

for _, m := range c.config.Mounts {
if m.Device == "bind" {
mountDest := m.Destination
if strings.HasPrefix(mountDest, c.config.Rootfs) {
mountDest = mountDest[len(c.config.Rootfs):]
switch m.Device {
case "bind":
c.addCriuDumpMount(req, m)
break
case "cgroup":
binds, err := getCgroupMounts(m)
if err != nil {
return err
}

extMnt := new(criurpc.ExtMountMap)
extMnt.Key = proto.String(mountDest)
extMnt.Val = proto.String(mountDest)
req.Opts.ExtMnt = append(req.Opts.ExtMnt, extMnt)
for _, b := range binds {
c.addCriuDumpMount(req, b)
}
break
}
}

Expand All @@ -387,13 +403,26 @@ func (c *linuxContainer) Checkpoint(criuOpts *CriuOpts) error {
return err
}

err = c.criuSwrk(nil, &req, criuOpts)
err = c.criuSwrk(nil, req, criuOpts)
if err != nil {
return err
}
return nil
}

func (c *linuxContainer) addCriuRestoreMount(req *criurpc.CriuReq, m *configs.Mount) {
mountDest := m.Destination
if strings.HasPrefix(mountDest, c.config.Rootfs) {
mountDest = mountDest[len(c.config.Rootfs):]
}

extMnt := &criurpc.ExtMountMap{
Key: proto.String(mountDest),
Val: proto.String(m.Source),
}
req.Opts.ExtMnt = append(req.Opts.ExtMnt, extMnt)
}

func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
c.m.Lock()
defer c.m.Unlock()
Expand Down Expand Up @@ -449,7 +478,7 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
defer syscall.Unmount(root, syscall.MNT_DETACH)

t := criurpc.CriuReqType_RESTORE
req := criurpc.CriuReq{
req := &criurpc.CriuReq{
Type: &t,
Opts: &criurpc.CriuOpts{
ImagesDirFd: proto.Int32(int32(imageDir.Fd())),
Expand All @@ -468,16 +497,19 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
},
}
for _, m := range c.config.Mounts {
if m.Device == "bind" {
mountDest := m.Destination
if strings.HasPrefix(mountDest, c.config.Rootfs) {
mountDest = mountDest[len(c.config.Rootfs):]
switch m.Device {
case "bind":
c.addCriuRestoreMount(req, m)
break
case "cgroup":
binds, err := getCgroupMounts(m)
if err != nil {
return err
}

extMnt := new(criurpc.ExtMountMap)
extMnt.Key = proto.String(mountDest)
extMnt.Val = proto.String(m.Source)
req.Opts.ExtMnt = append(req.Opts.ExtMnt, extMnt)
for _, b := range binds {
c.addCriuRestoreMount(req, b)
}
break
}
}
for _, iface := range c.config.Networks {
Expand Down Expand Up @@ -515,7 +547,7 @@ func (c *linuxContainer) Restore(process *Process, criuOpts *CriuOpts) error {
}
}

err = c.criuSwrk(process, &req, criuOpts)
err = c.criuSwrk(process, req, criuOpts)
if err != nil {
return err
}
Expand Down
47 changes: 29 additions & 18 deletions libcontainer/rootfs_linux.go
View file
Expand Up @@ -170,27 +170,10 @@ func mountToRootfs(m *configs.Mount, rootfs, mountLabel string) error {
}
}
case "cgroup":
mounts, err := cgroups.GetCgroupMounts()
binds, err := getCgroupMounts(m)
if err != nil {
return err
}
var binds []*configs.Mount
for _, mm := range mounts {
dir, err := mm.GetThisCgroupDir()
if err != nil {
return err
}
relDir, err := filepath.Rel(mm.Root, dir)
if err != nil {
return err
}
binds = append(binds, &configs.Mount{
Device: "bind",
Source: filepath.Join(mm.Mountpoint, relDir),
Destination: filepath.Join(m.Destination, strings.Join(mm.Subsystems, ",")),
Flags: syscall.MS_BIND | syscall.MS_REC | m.Flags,
})
}
tmpfs := &configs.Mount{
Source: "tmpfs",
Device: "tmpfs",
Expand All @@ -211,6 +194,34 @@ func mountToRootfs(m *configs.Mount, rootfs, mountLabel string) error {
return nil
}

func getCgroupMounts(m *configs.Mount) ([]*configs.Mount, error) {
mounts, err := cgroups.GetCgroupMounts()
if err != nil {
return nil, err
}

var binds []*configs.Mount

for _, mm := range mounts {
dir, err := mm.GetThisCgroupDir()
if err != nil {
return nil, err
}
relDir, err := filepath.Rel(mm.Root, dir)
if err != nil {
return nil, err
}
binds = append(binds, &configs.Mount{
Device: "bind",
Source: filepath.Join(mm.Mountpoint, relDir),
Destination: filepath.Join(m.Destination, strings.Join(mm.Subsystems, ",")),
Flags: syscall.MS_BIND | syscall.MS_REC | m.Flags,
})
}

return binds, nil
}

// checkMountDestination checks to ensure that the mount destination is not over the
// top of /proc or /sys.
// dest is required to be an abs path and have any symlinks resolved before calling this function.
Expand Down

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