Re: [PATCH v6 1/2] fs/resctrl: Report invalid domain ID when parsing io_alloc_cbm

[Reinette Chatre]

Hi Aaron,

On 3/24/26 5:11 PM, Aaron Tomlin wrote:
> The last_cmd_status file is intended to report details about the most
> recent resctrl filesystem operation, specifically to aid in diagnosing
> failures.
> 
> However, when parsing io_alloc_cbm, if a user provides a domain ID that
> does not exist in the resource, the operation fails with -EINVAL without
> updating last_cmd_status. This results in inconsistent behaviour where
> the system call returns an error, but last_cmd_status misleadingly reports
> "ok", leaving the user unaware that the failure was caused by an invalid
> domain ID.
> 
> Write an error message to last_cmd_status when the target domain ID cannot
> be found.
> 
> Fixes: 28fa2cce7a83 ("fs/resctrl: Introduce interface to modify io_alloc capacity bitmasks")
> Suggested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxxx>
> ---

Thank you.

Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>

Reinette