[dm-devel] [PATCH v2 09/10] multipathd: improve "add missing path" handling

[Benjamin Marzinski]

On Tue, Oct 23, 2018 at 03:43:47PM +0200, Martin Wilck wrote:
> Only add devices that have been properly initialized by pathinfo().
> For others, increase the path check interval to avoid useless checks
> of devices which are probably not meant to be multipathed anyway.
> 
> The check for pp->initialized != INIT_MISSING_UDEV is redundant,
> as check_path() returns early in all other cases. Replace it by a
> check for INIT_FAILED, in case we ever add more init states.
> 

Thanks

Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>

> Suggested-by: Benjamin Marzinski <bmarzins at redhat.com>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>  multipathd/main.c | 23 ++++++++++++++---------
>  1 file changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/multipathd/main.c b/multipathd/main.c
> index a9e1a4bd..bf5f12a6 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -1811,7 +1811,7 @@ check_path (struct vectors * vecs, struct path * pp, int ticks)
>  	int add_active;
>  	int disable_reinstate = 0;
>  	int oldchkrstate = pp->chkrstate;
> -	int retrigger_tries, checkint;
> +	int retrigger_tries, checkint, max_checkint;
>  	struct config *conf;
>  	int ret;
>  
> @@ -1827,6 +1827,7 @@ check_path (struct vectors * vecs, struct path * pp, int ticks)
>  	conf = get_multipath_config();
>  	retrigger_tries = conf->retrigger_tries;
>  	checkint = conf->checkint;
> +	max_checkint = conf->max_checkint;
>  	put_multipath_config(conf);
>  	if (!pp->mpp && pp->initialized == INIT_MISSING_UDEV) {
>  		if (pp->retriggers < retrigger_tries) {
> @@ -1891,18 +1892,26 @@ check_path (struct vectors * vecs, struct path * pp, int ticks)
>  		return 1;
>  	}
>  	if (!pp->mpp) {
> -		if (!strlen(pp->wwid) && pp->initialized != INIT_MISSING_UDEV &&
> +		if (!strlen(pp->wwid) && pp->initialized == INIT_FAILED &&
>  		    (newstate == PATH_UP || newstate == PATH_GHOST)) {
>  			condlog(2, "%s: add missing path", pp->dev);
>  			conf = get_multipath_config();
>  			pthread_cleanup_push(put_multipath_config, conf);
>  			ret = pathinfo(pp, conf, DI_ALL | DI_BLACKLIST);
>  			pthread_cleanup_pop(1);
> -			if (ret == PATHINFO_OK) {
> +			/* INIT_OK implies ret == PATHINFO_OK */
> +			if (pp->initialized == INIT_OK) {
>  				ev_add_path(pp, vecs, 1);
>  				pp->tick = 1;
> -			} else if (ret == PATHINFO_SKIPPED)
> -				return -1;
> +			} else {
> +				/*
> +				 * We failed multiple times to initialize this
> +				 * path properly. Don't re-check too often.
> +				 */
> +				pp->checkint = max_checkint;
> +				if (ret == PATHINFO_SKIPPED)
> +					return -1;
> +			}
>  		}
>  		return 0;
>  	}
> @@ -2049,11 +2058,7 @@ check_path (struct vectors * vecs, struct path * pp, int ticks)
>  				return 0;
>  			}
>  		} else {
> -			unsigned int max_checkint;
>  			LOG_MSG(4, checker_message(&pp->checker));
> -			conf = get_multipath_config();
> -			max_checkint = conf->max_checkint;
> -			put_multipath_config(conf);
>  			if (pp->checkint != max_checkint) {
>  				/*
>  				 * double the next check delay.
> -- 
> 2.19.1