Re: [PATCH 02/11] tools/xenstored: add central quota check functions

["Anthony PERARD" <anthony.perard@vates.tech>]

On Thu, Mar 05, 2026 at 02:51:59PM +0100, Juergen Gross wrote:
> Add central functions for checking a value (either an absolute one or
> the current domain value plus an offset) against a specific quota.
> 
> This is in preparation of introducing per-domain quota.
> 
> The required changes allow to drop the "update" parameter from
> domain_nbentry_fix().

This patch changes the return value of do_watch(), from E2BIG to ENOSPC,
but that's not mention.

> diff --git a/tools/xenstored/domain.c b/tools/xenstored/domain.c
> index e453b3061f..1df9265ad5 100644
> --- a/tools/xenstored/domain.c
> +++ b/tools/xenstored/domain.c
> @@ -490,10 +509,9 @@ static bool domain_can_read(struct connection *conn)
>  	if (domain_is_unprivileged(conn)) {
>  		if (domain->wrl_credit < 0)
>  			return false;
> -		if (domain->acc[ACC_OUTST].val >= hard_quotas[ACC_OUTST].val)
> +		if (domain_check_quota_add(domain, ACC_OUTST, 0))

Is this change fixing a potential bug? As now we check if there's a
quota for OUTST.

>  			return false;
> -		if (domain->acc[ACC_MEM].val >= hard_quotas[ACC_MEM].val &&
> -		    hard_quotas[ACC_MEM].val)
> +		if (domain_check_quota_add(domain, ACC_MEM, 0))
>  			return false;
>  	}
>  
> diff --git a/tools/xenstored/watch.c b/tools/xenstored/watch.c
> index b66a9f1a39..36e4d33f22 100644
> --- a/tools/xenstored/watch.c
> +++ b/tools/xenstored/watch.c
> @@ -220,8 +220,8 @@ int do_watch(const void *ctx, struct connection *conn, struct buffered_data *in)
>  			return EEXIST;
>  	}
>  
> -	if (domain_watch(conn) > hard_quotas[ACC_WATCH].val)
> -		return E2BIG;
> +	if (domain_check_quota_add(conn->domain, ACC_WATCH, 1))
> +		return ENOSPC;

Change of return value here not mentionned, even if it now aligned with
the value returned in other places.

>  
>  	watch = add_watch(conn, vec[0], vec[1], relative, false);
>  	if (!watch)

Patch looks fine to me:
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>

Thanks,


--
Anthony Perard | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech