[dm-devel] [PATCH 8/8] multipathd: handle repeated udev retrigger failure

[Martin Wilck]

If a path was still not properly initialized after exhausting the
retrigger tries, it used to remain in INIT_MISSING_UDEV state forever.
get_uid() might fall back to non-udev-based methods to determine
the WWID, but it would never be called for a path in this state any more.

This patch changes this behavior by resetting the path back to FAILED
state if udev can't provide the WWID even after retriggering. Now, if
the path ever happens to be in PATH_UP or PATH_GHOST state again,
pathinfo(DI_ALL) will be called from check_path(), and there's at least
some chance to obtain a WWID for it.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 multipathd/main.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/multipathd/main.c b/multipathd/main.c
index 2d45d989..a9e1a4bd 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -1828,15 +1828,29 @@ check_path (struct vectors * vecs, struct path * pp, int ticks)
 	retrigger_tries = conf->retrigger_tries;
 	checkint = conf->checkint;
 	put_multipath_config(conf);
-	if (!pp->mpp && pp->initialized == INIT_MISSING_UDEV &&
-	    pp->retriggers < retrigger_tries) {
-		condlog(2, "%s: triggering change event to reinitialize",
-			pp->dev);
-		pp->initialized = INIT_REQUESTED_UDEV;
-		pp->retriggers++;
-		sysfs_attr_set_value(pp->udev, "uevent", "change",
-				     strlen("change"));
-		return 0;
+	if (!pp->mpp && pp->initialized == INIT_MISSING_UDEV) {
+		if (pp->retriggers < retrigger_tries) {
+			condlog(2, "%s: triggering change event to reinitialize",
+				pp->dev);
+			pp->initialized = INIT_REQUESTED_UDEV;
+			pp->retriggers++;
+			sysfs_attr_set_value(pp->udev, "uevent", "change",
+					     strlen("change"));
+			return 0;
+		} else {
+			condlog(1, "%s: not initialized after %d udev retriggers",
+				pp->dev, retrigger_tries);
+			/*
+			 * Make sure that the "add missing path" code path
+			 * below may reinstate the path later, if it ever
+			 * comes up again.
+			 * The WWID needs not be cleared; if it was set, the
+			 * state hadn't been INIT_MISSING_UDEV in the first
+			 * place.
+			 */
+			pp->initialized = INIT_FAILED;
+			return 0;
+		}
 	}
 
 	/*
-- 
2.19.0