[dm-devel] [PATCH 53/57] multipathd: implement 'show map $map format $fmt'

[Benjamin Marzinski]

On Wed, Apr 27, 2016 at 01:10:54PM +0200, Hannes Reinecke wrote:
> Similar to the existing 'show map $map topology', but allowing
> formatted content.

This touches on a patch I've thought about writing, but never got around
to.  The issue is that with show_maps_topology() we call
update_multipath() to make sure we sync our state with the kernel before
returning it, but with show_maps(), we don't. Before we could change the
format, there was no point in updating the state in show_maps (and now,
in show_map). But now that we can get all that information, it might be
worth it.

On the other hand, update_multipath() might be more than we need.
update_multipath_strings() might be enought. And unlike when we first
wrote show_maps_topology(), we call update_multipath_strings() when we
check a path now.

I'm not sure what the best answer is, but I've considered adding (or
replacing update_multipath with) update_multipath_strings in all the map
showing functions, for consistency's sake.

but besides that thought, the patch looks fine.

-Ben

> 
> Signed-off-by: Hannes Reinecke <hare at suse.de>
> ---
>  multipathd/cli.c          |  2 ++
>  multipathd/cli_handlers.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++
>  multipathd/cli_handlers.h |  2 ++
>  multipathd/main.c         |  2 ++
>  4 files changed, 73 insertions(+)
> 
> diff --git a/multipathd/cli.c b/multipathd/cli.c
> index ab1365b..3c9cdbf 100644
> --- a/multipathd/cli.c
> +++ b/multipathd/cli.c
> @@ -497,6 +497,8 @@ cli_init (void) {
>  	add_handler(LIST+MAPS+TOPOLOGY, NULL);
>  	add_handler(LIST+TOPOLOGY, NULL);
>  	add_handler(LIST+MAP+TOPOLOGY, NULL);
> +	add_handler(LIST+MAP+FMT, NULL);
> +	add_handler(LIST+MAP+RAW+FMT, NULL);
>  	add_handler(LIST+CONFIG, NULL);
>  	add_handler(LIST+BLACKLIST, NULL);
>  	add_handler(LIST+DEVICES, NULL);
> diff --git a/multipathd/cli_handlers.c b/multipathd/cli_handlers.c
> index 886a5fd..dbdcbc2 100644
> --- a/multipathd/cli_handlers.c
> +++ b/multipathd/cli_handlers.c
> @@ -349,6 +349,33 @@ show_daemon (char ** r, int *len)
>  }
>  
>  int
> +show_map (char ** r, int *len, struct multipath * mpp, char * style,
> +	  int pretty)
> +{
> +	char * c;
> +	char * reply;
> +	unsigned int maxlen = INITIAL_REPLY_LEN;
> +	int again = 1;
> +
> +	reply = MALLOC(maxlen);
> +	while (again) {
> +		if (!reply)
> +			return 1;
> +
> +		c = reply;
> +		c += snprint_multipath(c, reply + maxlen - c, style,
> +				       mpp, pretty);
> +
> +		again = ((c - reply) == (maxlen - 1));
> +
> +		REALLOC_REPLY(reply, again, maxlen);
> +	}
> +	*r = reply;
> +	*len = (int)(c - reply + 1);
> +	return 0;
> +}
> +
> +int
>  show_maps (char ** r, int *len, struct vectors * vecs, char * style,
>  	   int pretty)
>  {
> @@ -407,6 +434,46 @@ cli_list_maps_raw (void * v, char ** reply, int * len, void * data)
>  }
>  
>  int
> +cli_list_map_fmt (void * v, char ** reply, int * len, void * data)
> +{
> +	struct multipath * mpp;
> +	struct vectors * vecs = (struct vectors *)data;
> +	char * param = get_keyparam(v, MAP);
> +	char * fmt = get_keyparam(v, FMT);
> +
> +	param = convert_dev(param, 0);
> +	get_path_layout(vecs->pathvec, 0);
> +	get_multipath_layout(vecs->mpvec, 1);
> +	mpp = find_mp_by_str(vecs->mpvec, param);
> +	if (!mpp)
> +		return 1;
> +
> +	condlog(3, "list map %s fmt %s (operator)", param, fmt);
> +
> +	return show_map(reply, len, mpp, fmt, 1);
> +}
> +
> +int
> +cli_list_map_raw (void * v, char ** reply, int * len, void * data)
> +{
> +	struct multipath * mpp;
> +	struct vectors * vecs = (struct vectors *)data;
> +	char * param = get_keyparam(v, MAP);
> +	char * fmt = get_keyparam(v, FMT);
> +
> +	param = convert_dev(param, 0);
> +	get_path_layout(vecs->pathvec, 0);
> +	get_multipath_layout(vecs->mpvec, 1);
> +	mpp = find_mp_by_str(vecs->mpvec, param);
> +	if (!mpp)
> +		return 1;
> +
> +	condlog(3, "list map %s fmt %s (operator)", param, fmt);
> +
> +	return show_map(reply, len, mpp, fmt, 0);
> +}
> +
> +int
>  cli_list_maps (void * v, char ** reply, int * len, void * data)
>  {
>  	struct vectors * vecs = (struct vectors *)data;
> diff --git a/multipathd/cli_handlers.h b/multipathd/cli_handlers.h
> index 799f8da..5d51018 100644
> --- a/multipathd/cli_handlers.h
> +++ b/multipathd/cli_handlers.h
> @@ -7,6 +7,8 @@ int cli_list_daemon (void * v, char ** reply, int * len, void * data);
>  int cli_list_maps (void * v, char ** reply, int * len, void * data);
>  int cli_list_maps_fmt (void * v, char ** reply, int * len, void * data);
>  int cli_list_maps_raw (void * v, char ** reply, int * len, void * data);
> +int cli_list_map_fmt (void * v, char ** reply, int * len, void * data);
> +int cli_list_map_raw (void * v, char ** reply, int * len, void * data);
>  int cli_list_maps_status (void * v, char ** reply, int * len, void * data);
>  int cli_list_maps_stats (void * v, char ** reply, int * len, void * data);
>  int cli_list_map_topology (void * v, char ** reply, int * len, void * data);
> diff --git a/multipathd/main.c b/multipathd/main.c
> index d8fa88f..a58dae5 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -990,6 +990,8 @@ uxlsnrloop (void * ap)
>  	set_handler_callback(LIST+MAPS+TOPOLOGY, cli_list_maps_topology);
>  	set_handler_callback(LIST+TOPOLOGY, cli_list_maps_topology);
>  	set_handler_callback(LIST+MAP+TOPOLOGY, cli_list_map_topology);
> +	set_handler_callback(LIST+MAP+FMT, cli_list_map_fmt);
> +	set_handler_callback(LIST+MAP+RAW+FMT, cli_list_map_fmt);
>  	set_handler_callback(LIST+CONFIG, cli_list_config);
>  	set_handler_callback(LIST+BLACKLIST, cli_list_blacklist);
>  	set_handler_callback(LIST+DEVICES, cli_list_devices);
> -- 
> 2.6.6