[dm-devel] [PATCH 12/21] libmultipath/checkers: support unsupported paths

[Benjamin Marzinski]

On Fri, Oct 12, 2018 at 12:26:58AM +0200, Martin Wilck wrote:
> We should be able to distinguish the case where a checker
> determines a path to be positively down from the case where
> the checker fails to obtain necessary information, e.g.
> because of a configuration problem (wrong checker).
> Use PATH_WILD for the latter case, as it's hardly used now.
> 
> Provide a generic message for the situation that a path
> checker can't handle a certain path.
> 

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

> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>  libmultipath/checkers.c | 1 +
>  libmultipath/checkers.h | 7 +++++--
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/libmultipath/checkers.c b/libmultipath/checkers.c
> index 359791ff..19c8ad58 100644
> --- a/libmultipath/checkers.c
> +++ b/libmultipath/checkers.c
> @@ -279,6 +279,7 @@ static const char *generic_msg[CHECKER_LAST_GENERIC_MSGID] = {
>  	[CHECKER_MSGID_UP] = " reports path is up",
>  	[CHECKER_MSGID_DOWN] = " reports path is down",
>  	[CHECKER_MSGID_GHOST] = " reports path is ghost",
> +	[CHECKER_MSGID_UNSUPPORTED] = " doesn't support this device",
>  };
>  
>  static const char *_checker_message(const struct checker *c)
> diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h
> index b48f4dc2..98fec2c4 100644
> --- a/libmultipath/checkers.h
> +++ b/libmultipath/checkers.h
> @@ -10,8 +10,10 @@
>   * Userspace (multipath/multipathd) path states
>   *
>   * PATH_WILD:
> - * - Use: None of the checkers (returned if we don't have an fd)
> - * - Description: Corner case where "fd < 0" for path fd (see checker_check())
> + * - Use: Any checker
> + * - Description: Corner case where "fd < 0" for path fd (see checker_check()),
> + *   or where a checker detects an unsupported device
> + *   (e.g. wrong checker configured for a given device).
>   *
>   * PATH_UNCHECKED:
>   * - Use: Only in directio checker
> @@ -108,6 +110,7 @@ enum {
>  	CHECKER_MSGID_UP,
>  	CHECKER_MSGID_DOWN,
>  	CHECKER_MSGID_GHOST,
> +	CHECKER_MSGID_UNSUPPORTED,
>  	CHECKER_LAST_GENERIC_MSGID,
>  	CHECKER_FIRST_MSGID = 100,	/* lowest msgid for checkers */
>  	CHECKER_MSGTABLE_SIZE = 100,	/* max msg table size for checkers */
> -- 
> 2.19.0