Re: [PATCH v2 04/14] multipathd: quickly re-sync if a map is inconsistent

[Benjamin Marzinski <bmarzins@redhat.com>]

On Wed, Dec 11, 2024 at 11:58:59PM +0100, Martin Wilck wrote:
> After reading the kernel device-mapper table, update_pathvec_from_dm()
> sets the mpp->need_reload flag if an inconsistent state was found (often a
> path with wrong WWID). We expect reload_and_sync_map() to fix this situation.
> However, schedule a quick resync in this case, to be double-check that the
> inconsistency has been fixed.

Like I mentioned in by second comment to patch 03, this sync already
happens as part of reload_and_sync_map().

> 
> Signed-off-by: Martin Wilck <mwilck@suse.com>
> ---
>  multipathd/main.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/multipathd/main.c b/multipathd/main.c
> index e4e6bf7..178618c 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -3026,13 +3026,22 @@ checkerloop (void *ap)
>  							     start_time.tv_sec);
>  			if (checker_state == CHECKER_FINISHED) {
>  				vector_foreach_slot(vecs->mpvec, mpp, i) {
> +					bool inconsistent;
> +
>  					sync_mpp(vecs, mpp, ticks);
> -					if ((update_mpp_prio(mpp) || mpp->need_reload) &&
> +					inconsistent = mpp->need_reload;
> +					if ((update_mpp_prio(mpp) || inconsistent) &&
>  					    reload_and_sync_map(mpp, vecs) == 2) {
>  						/* multipath device deleted */
>  						i--;
>  						continue;
>  					}
> +					/*
> +					 * If we reloaded due to inconsistent state,
> +					 * schedule another sync at the next tick.
> +					 */
> +					if (inconsistent)
> +						mpp->sync_tick = 1;
>  				}
>  			}
>  			lock_cleanup_pop(vecs->lock);
> -- 
> 2.47.0