diff --git a/libcontainer/criu_linux.go b/libcontainer/criu_linux.go index dbeb722a2eb..a86e53fd785 100644 --- a/libcontainer/criu_linux.go +++ b/libcontainer/criu_linux.go @@ -523,34 +523,9 @@ func (c *Container) restoreNetwork(req *criurpc.CriuReq, criuOpts *CriuOpts) { } } -// makeCriuRestoreMountpoints makes the actual mountpoints for the -// restore using CRIU. This function is inspired from the code in -// rootfs_linux.go. -func (c *Container) makeCriuRestoreMountpoints(m *configs.Mount) error { - if m.Device == "cgroup" { - // No mount point(s) need to be created: - // - // * for v1, mount points are saved by CRIU because - // /sys/fs/cgroup is a tmpfs mount - // - // * for v2, /sys/fs/cgroup is a real mount, but - // the mountpoint appears as soon as /sys is mounted - return nil - } - // TODO: pass srcFD? Not sure if criu is impacted by issue #2484. - me := mountEntry{Mount: m} - // For all other filesystems, just make the target. - if _, err := createMountpoint(c.config.Rootfs, me); err != nil { - return fmt.Errorf("create criu restore mountpoint for %s mount: %w", me.Destination, err) - } - return nil -} - -// isPathInPrefixList is a small function for CRIU restore to make sure -// mountpoints, which are on a tmpfs, are not created in the roofs. -func isPathInPrefixList(path string, prefix []string) bool { - for _, p := range prefix { - if strings.HasPrefix(path, p+"/") { +func isOnTmpfs(path string, mounts []*configs.Mount) bool { + for _, m := range mounts { + if m.Device == "tmpfs" && strings.HasPrefix(path, m.Destination+"/") { return true } } @@ -564,17 +539,6 @@ func isPathInPrefixList(path string, prefix []string) bool { // This function also creates missing mountpoints as long as they // are not on top of a tmpfs, as CRIU will restore tmpfs content anyway. func (c *Container) prepareCriuRestoreMounts(mounts []*configs.Mount) error { - // First get a list of a all tmpfs mounts - tmpfs := []string{} - for _, m := range mounts { - switch m.Device { - case "tmpfs": - tmpfs = append(tmpfs, m.Destination) - } - } - // Now go through all mounts and create the mountpoints - // if the mountpoints are not on a tmpfs, as CRIU will - // restore the complete tmpfs content from its checkpoint. umounts := []string{} defer func() { for _, u := range umounts { @@ -590,28 +554,40 @@ func (c *Container) prepareCriuRestoreMounts(mounts []*configs.Mount) error { }) } }() + // Now go through all mounts and create the required mountpoints. for _, m := range mounts { - if !isPathInPrefixList(m.Destination, tmpfs) { - if err := c.makeCriuRestoreMountpoints(m); err != nil { + // No cgroup mount point(s) need to be created: + // * for v1, mount points are saved by CRIU because + // /sys/fs/cgroup is a tmpfs mount; + // * for v2, /sys/fs/cgroup is a real mount, but + // the mountpoint appears as soon as /sys is mounted. + if m.Device == "cgroup" { + continue + } + // If the mountpoint is on a tmpfs, skip it as CRIU will + // restore the complete tmpfs content from its checkpoint. + if isOnTmpfs(m.Destination, mounts) { + continue + } + if _, err := createMountpoint(c.config.Rootfs, mountEntry{Mount: m}); err != nil { + return fmt.Errorf("create criu restore mountpoint for %s mount: %w", m.Destination, err) + } + // If the mount point is a bind mount, we need to mount + // it now so that runc can create the necessary mount + // points for mounts in bind mounts. + // This also happens during initial container creation. + // Without this CRIU restore will fail + // See: https://github.com/opencontainers/runc/issues/2748 + // It is also not necessary to order the mount points + // because during initial container creation mounts are + // set up in the order they are configured. + if m.Device == "bind" { + if err := utils.WithProcfd(c.config.Rootfs, m.Destination, func(dstFd string) error { + return mountViaFds(m.Source, nil, m.Destination, dstFd, "", unix.MS_BIND|unix.MS_REC, "") + }); err != nil { return err } - // If the mount point is a bind mount, we need to mount - // it now so that runc can create the necessary mount - // points for mounts in bind mounts. - // This also happens during initial container creation. - // Without this CRIU restore will fail - // See: https://github.com/opencontainers/runc/issues/2748 - // It is also not necessary to order the mount points - // because during initial container creation mounts are - // set up in the order they are configured. - if m.Device == "bind" { - if err := utils.WithProcfd(c.config.Rootfs, m.Destination, func(dstFd string) error { - return mountViaFds(m.Source, nil, m.Destination, dstFd, "", unix.MS_BIND|unix.MS_REC, "") - }); err != nil { - return err - } - umounts = append(umounts, m.Destination) - } + umounts = append(umounts, m.Destination) } } return nil