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

[Martin Wilck <mwilck@suse.com>]

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.

Signed-off-by: Martin Wilck <mwilck@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