[CRIU] [PATCH 1/2] restore: don't pass cgroup nsroot= option to mount()

[Pavel Emelyanov]

On 03/24/2016 12:41 AM, Tycho Andersen wrote:
> https://lkml.org/lkml/2016/3/21/777 introduces a new cgroup mount option
> called nsroot, but doesn't allow you to pass it to mount() to actually
> mount it. Let's chop this option off so that we don't get errors from
> mount().

What if this option comes in the middle of the options string?

> There may be better places to chop this off (e.g. perhaps on dump),
> although I think it is useful to have it in there for debugging purposes,
> and only costs us a few extra bytes to keep it in the images since we're
> going to have other cgroup options anyways.
> 
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
>  criu/mount.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/criu/mount.c b/criu/mount.c
> index a425828..be79999 100644
> --- a/criu/mount.c
> +++ b/criu/mount.c
> @@ -2866,6 +2866,18 @@ static int collect_mnt_from_image(struct mount_info **pms, struct ns_id *nsid)
>  		/* FIXME: abort unsupported early */
>  		pm->fstype = decode_fstype(me->fstype, me->fsname);
>  
> +		if (pm->fstype->code == FSTYPE__CGROUP) {
> +			char *pos;
> +
> +			pos = strstr(pm->options, "nsroot=");
> +			if (pos > pm->options && *(pos-1) == ',')
> +				pos--;
> +			if (pos) {
> +				pr_info("trimming nsroot option %s from cgroup mount\n", pos);
> +				*pos = 0;
> +			}
> +		}
> +
>  		if (get_mp_root(me, pm))
>  			goto err;
>  
>