[dm-devel] [PATCH v2 10/20] libmultipath: indicate wwid failure in dm_addmap_create()

[Martin Wilck]

dm_addmap_create() is where we actually try to set up a new
multipath map. Depending on the result, mark the wwid as
failed (or not), and re-trigger an uevent if necessary.
If a path changes from multipath to non-multipath, use an "add"
event to make sure LVM2 rules pick it up. Increase log level
of this event to 3.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/configure.c | 37 ++++++++++++++++++++++++++++---------
 libmultipath/configure.h |  2 +-
 libmultipath/devmapper.c |  8 +++++++-
 libmultipath/structs.h   |  1 +
 multipathd/main.c        |  2 +-
 5 files changed, 38 insertions(+), 12 deletions(-)

diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index 838d145a5aa2..88e6687849f8 100644
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -443,11 +443,18 @@ trigger_udev_change(const struct multipath *mpp)
 }
 
 void
-trigger_paths_udev_change(const struct multipath *mpp)
+trigger_paths_udev_change(struct multipath *mpp, bool is_mpath)
 {
 	struct pathgroup * pgp;
 	struct path * pp;
 	int i, j;
+	/*
+	 * If a path changes from multipath to non-multipath, we must
+	 * synthesize an artificial "add" event, otherwise the LVM2 rules
+	 * (69-lvm2-lvmetad.rules) won't pick it up. Otherwise, we'd just
+	 * irritate ourselves with an "add", so use "change".
+	 */
+	const char *action = is_mpath ? "change" : "add";
 
 	if (!mpp || !mpp->pg)
 		return;
@@ -466,14 +473,21 @@ trigger_paths_udev_change(const struct multipath *mpp)
 			 */
 			env = udev_device_get_property_value(
 				pp->udev, "DM_MULTIPATH_DEVICE_PATH");
-			if (env != NULL && !strcmp(env, "1"))
-					continue;
 
-			condlog(4, "triggering change uevent for %s", pp->dev);
-			sysfs_attr_set_value(pp->udev, "uevent", "change",
-					     strlen("change"));
+			if (is_mpath && env != NULL && !strcmp(env, "1"))
+				continue;
+			else if (!is_mpath &&
+				   (env == NULL || !strcmp(env, "0")))
+				continue;
+
+			condlog(3, "triggering %s uevent for %s (is %smultipath member)",
+				action, pp->dev, is_mpath ? "" : "no ");
+			sysfs_attr_set_value(pp->udev, "uevent",
+					     action, strlen(action));
 		}
 	}
+
+	mpp->needs_paths_uevent = 0;
 }
 
 static int
@@ -870,8 +884,10 @@ int domap(struct multipath *mpp, char *params, int is_daemon)
 		 * succeeded
 		 */
 		mpp->force_udev_reload = 0;
-		if (mpp->action == ACT_CREATE && remember_wwid(mpp->wwid) == 1)
-			trigger_paths_udev_change(mpp);
+		if (mpp->action == ACT_CREATE &&
+		    (remember_wwid(mpp->wwid) == 1 ||
+		     mpp->needs_paths_uevent))
+			trigger_paths_udev_change(mpp, true);
 		if (!is_daemon) {
 			/* multipath client mode */
 			dm_switchgroup(mpp->alias, mpp->bestpg);
@@ -896,7 +912,10 @@ int domap(struct multipath *mpp, char *params, int is_daemon)
 		}
 		dm_setgeometry(mpp);
 		return DOMAP_OK;
-	}
+	} else if (r == DOMAP_FAIL && mpp->action == ACT_CREATE &&
+		   mpp->needs_paths_uevent)
+		trigger_paths_udev_change(mpp, false);
+
 	return DOMAP_FAIL;
 }
 
diff --git a/libmultipath/configure.h b/libmultipath/configure.h
index 545cbc209793..8b56d33a1d0b 100644
--- a/libmultipath/configure.h
+++ b/libmultipath/configure.h
@@ -37,4 +37,4 @@ int get_refwwid (enum mpath_cmds cmd, char * dev, enum devtypes dev_type,
 		 vector pathvec, char **wwid);
 int reload_map(struct vectors *vecs, struct multipath *mpp, int refresh, int is_daemon);
 struct udev_device *get_udev_device(const char *dev, enum devtypes dev_type);
-void trigger_paths_udev_change(const struct multipath *mpp);
+void trigger_paths_udev_change(struct multipath *mpp, bool is_mpath);
diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index 9bafbc6a239a..bd595f4fa40b 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -22,6 +22,7 @@
 #include "devmapper.h"
 #include "sysfs.h"
 #include "config.h"
+#include "wwids.h"
 
 #include "log_pthread.h"
 #include <sys/types.h>
@@ -411,8 +412,11 @@ int dm_addmap_create (struct multipath *mpp, char * params)
 		int err;
 
 		if (dm_addmap(DM_DEVICE_CREATE, TGT_MPATH, mpp, params, ro,
-			      udev_flags))
+			      udev_flags)) {
+			if (unmark_failed_wwid(mpp->wwid) == 1)
+				mpp->needs_paths_uevent = 1;
 			return 1;
+		}
 		/*
 		 * DM_DEVICE_CREATE is actually DM_DEV_CREATE + DM_TABLE_LOAD.
 		 * Failing the second part leaves an empty map. Clean it up.
@@ -428,6 +432,8 @@ int dm_addmap_create (struct multipath *mpp, char * params)
 			break;
 		}
 	}
+	if (mark_failed_wwid(mpp->wwid) == 1)
+		mpp->needs_paths_uevent = 1;
 	return 0;
 }
 
diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index d6482f84f0e6..32f4b2d0696c 100644
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -322,6 +322,7 @@ struct multipath {
 	int max_sectors_kb;
 	int force_readonly;
 	int force_udev_reload;
+	int needs_paths_uevent;
 	int ghost_delay;
 	int ghost_delay_tick;
 	unsigned int dev_loss;
diff --git a/multipathd/main.c b/multipathd/main.c
index bfbe5f66b324..ea8c413f28c6 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -2310,7 +2310,7 @@ configure (struct vectors * vecs)
 	sync_maps_state(mpvec);
 	vector_foreach_slot(mpvec, mpp, i){
 		if (remember_wwid(mpp->wwid) == 1)
-			trigger_paths_udev_change(mpp);
+			trigger_paths_udev_change(mpp, true);
 		update_map_pr(mpp);
 	}
 
-- 
2.16.1