[CRIU] [PATCH 14/14] mount: don't open the same root twise

[Pavel Emelyanov]

On 04/17/2014 11:24 PM, Andrey Vagin wrote:
> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
>  mount.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/mount.c b/mount.c
> index 92c6a6c..72ec81d 100644
> --- a/mount.c
> +++ b/mount.c
> @@ -1789,10 +1789,15 @@ out:
>  
>  int mntns_collect_root(pid_t pid)
>  {
> +	static int mntns_root_pid = -1;
> +
>  	int fd, pfd;
>  	int ret;
>  	char path[PATH_MAX + 1];
>  
> +	if (mntns_root_pid == pid) /* The required root is already opened */
> +		return get_service_fd(ROOT_FD_OFF);
> +
>  	close_service_fd(ROOT_FD_OFF);
>  
>  	if (!(root_ns_mask & CLONE_NEWNS)) {
> @@ -1841,6 +1846,8 @@ int mntns_collect_root(pid_t pid)
>  
>  set_root:
>  	ret = install_service_fd(ROOT_FD_OFF, fd);
> +	if (ret >= 0)
> +		mntns_root_pid = pid;

If we're going to get mntns root fd always, I see no sense in service
FD. It's like open_proc_fd thing.

>  	close(fd);
>  	return ret;
>  }
>