[Devel] [PATCH RHEL7 COMMIT] vznetstat: Make sure the statistics is allocated for VE

[Konstantin Khorenko]

By this patch we fix the case when ipv6 vznetstat module is loaded while ipv4 is not (crash, as ip6_vznetstat believes vznetstat fields have been already allocated which is done currently in ip_vznetstat module)

Nevertheless the fix is not symmetric: in case "ip_vznetstat" module is loaded, netstat fields are allocated for all running Containers, while when "ip6_vznetstat" is loaded, already running Containers don't have vznet statistics.

=> suggestion to move allocation code into common separate code. In case either module is loaded, vznetstat fields should be allocated for all currently running Containers.

It will be done in the scope of https://jira.sw.ru/browse/PSBM-35011.

--
Best regards,

Konstantin Khorenko,
Virtuozzo Linux Kernel Team

On 07/17/2015 10:55 PM, Konstantin Khorenko wrote:
> The commit is pushed to "branch-rh7-3.10.0-123.1.2-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
> after rh7-3.10.0-123.1.2.vz7.5.25
> ------>
> commit 3ad7b9565dc63734b584ce1f4c67ffb5456aa306
> Author: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> Date:   Fri Jul 17 23:55:04 2015 +0400
> 
>     vznetstat: Make sure the statistics is allocated for VE
>     
>     Currently the ip_vznetstat doesn't allocate statistics for new
>     VEs but rather relies on fact that ip6_vznetstat module is loaded,
>     which is not always the true. It's rather messy at moment:
>     ip_vznetstat allocates stat for all existing VE's in module
>     init procedure, while ip6_vznetstat allocates statistics for
>     every new VE's, better might be to move all this stuff into
>     general vznetstat module in future.
>     
>     https://jira.sw.ru/browse/PSBM-34837
>     
>     Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
>     
>     CC: Andrey Vagin <avagin at virtuozzo.com>
>     CC: Vladimir Davydov <vdavydov at virtuozzo.com>
>     CC: Konstantin Khorenko <khorenko at virtuozzo.com>
>     CC: Igor Sukhih <igor at parallels.com>
> ---
>  kernel/ve/vznetstat/ip_vznetstat.c | 38 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
> 
> diff --git a/kernel/ve/vznetstat/ip_vznetstat.c b/kernel/ve/vznetstat/ip_vznetstat.c
> index 1eb637b..4fbadf2 100644
> --- a/kernel/ve/vznetstat/ip_vznetstat.c
> +++ b/kernel/ve/vznetstat/ip_vznetstat.c
> @@ -192,6 +192,42 @@ void ip_vznetstat_touch(void)
>  }
>  EXPORT_SYMBOL(ip_vznetstat_touch);
>  
> +static int init_venet_acct_ip_stat_hook(void *data)
> +{
> +	struct ve_struct *ve = (struct ve_struct *)data;
> +	struct venet_stat *stat;
> +
> +	if (!ve->stat) {
> +		stat = venet_acct_find_create_stat(ve->veid);
> +		if (!stat)
> +			return -ENOMEM;
> +		init_venet_acct_ip_stat(ve, stat);
> +	} else
> +		venet_acct_get_stat(ve->stat);
> +
> +	__module_get(THIS_MODULE);
> +	return 0;
> +}
> +
> +static void fini_venet_acct_ip_stat_hook(void *data)
> +{
> +	struct ve_struct *ve = (struct ve_struct *)data;
> +
> +	/* module was load after VE ? */
> +	if (!ve->stat)
> +		return;
> +
> +	venet_acct_put_stat(ve->stat);
> +	module_put(THIS_MODULE);
> +}
> +
> +static struct ve_hook venet_acct_ip_stat_hook = {
> +	.init		= init_venet_acct_ip_stat_hook,
> +	.fini		= fini_venet_acct_ip_stat_hook,
> +	.priority	= HOOK_PRIO_NET_ACCT,
> +	.owner		= THIS_MODULE,
> +};
> +
>  /*
>   * ---------------------------------------------------------------------------
>   * Initialization
> @@ -216,6 +252,7 @@ int __init ip_venetstat_init(void)
>  	if (ret < 0)
>  		goto err;
>  
> +	ve_hook_register(VE_SS_CHAIN, &venet_acct_ip_stat_hook);
>  	return 0;
>  err:
>  	mutex_lock(&ve_list_lock);
> @@ -233,6 +270,7 @@ void __exit ip_venetstat_exit(void)
>  	struct ve_struct *ve;
>  
>  	venet_acct_unregister_ip_hooks();
> +	ve_hook_unregister(&venet_acct_ip_stat_hook);
>  
>  	mutex_lock(&ve_list_lock);
>  	for_each_ve(ve) {
>