device-mapper-multipath/0144-multipathd-re-add-paths-skipped-because-they-were-of.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Wed, 2 Apr 2025 19:13:21 -0400
Subject: [PATCH] multipathd: re-add paths skipped because they were offline

When a new device is added by the multipath command, multipathd may know
of other paths that cannot be added to the device because they are
currently offline. Instead of ignoring these paths, multipathd will now
re-add them when they come back online. To do this, it multipathd needs
a new path variable add_when_online, to track devices that could not be
added to an existing multipath device because they were offline. These
paths are handled along with the other uninitialized paths.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
---
 libmultipath/libmultipath.version |  5 +++
 libmultipath/print.c              |  5 ++-
 libmultipath/structs.h            |  1 +
 libmultipath/structs_vec.c        |  5 +++
 multipathd/main.c                 | 53 ++++++++++++++++++++++++++++++-
 multipathd/multipathd.8           |  4 ++-
 6 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/libmultipath/libmultipath.version b/libmultipath/libmultipath.version
index e2cce8c7..46907278 100644
--- a/libmultipath/libmultipath.version
+++ b/libmultipath/libmultipath.version
@@ -313,3 +313,8 @@ global:
 	cleanup_udev_enumerate_ptr;
 	cleanup_udev_device_ptr;
 } LIBMULTIPATH_9.1.3;
+
+LIBMULTIPATH_9.1.5 {
+global:
+	can_recheck_wwid;
+} LIBMULTIPATH_9.1.4;
diff --git a/libmultipath/print.c b/libmultipath/print.c
index 4552fd43..ff224bc4 100644
--- a/libmultipath/print.c
+++ b/libmultipath/print.c
@@ -584,8 +584,11 @@ snprint_path_serial (struct strbuf *buff, const struct path * pp)
 static int
 snprint_path_mpp (struct strbuf *buff, const struct path * pp)
 {
-	if (!pp->mpp)
+	if (!pp->mpp) {
+		if (pp->add_when_online)
+			return append_strbuf_str(buff, "[offline]");
 		return append_strbuf_str(buff, "[orphan]");
+	}
 	if (!pp->mpp->alias)
 		return append_strbuf_str(buff, "[unknown]");
 	return snprint_str(buff, pp->mpp->alias);
diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index 4bf8c93a..0846e833 100644
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -374,6 +374,7 @@ struct path {
 	unsigned int dev_loss;
 	int eh_deadline;
 	bool can_use_env_uid;
+	bool add_when_online;
 	/* configlet pointers */
 	vector hwe;
 	struct gen_path generic_path;
diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index b8e304e0..7086781a 100644
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -319,6 +319,9 @@ void orphan_paths(vector pathvec, struct multipath *mpp, const char *reason)
 				free_path(pp);
 			} else
 				orphan_path(pp, reason);
+		} else if (pp->add_when_online &&
+			   strncmp(mpp->wwid, pp->wwid, WWID_SIZE) == 0) {
+			pp->add_when_online = false;
 		}
 	}
 }
@@ -496,6 +499,8 @@ void sync_paths(struct multipath *mpp, vector pathvec)
 		found = 0;
 		vector_foreach_slot(mpp->pg, pgp, j) {
 			if (find_slot(pgp->paths, (void *)pp) != -1) {
+				if (pp->add_when_online)
+					pp->add_when_online = false;
 				found = 1;
 				break;
 			}
diff --git a/multipathd/main.c b/multipathd/main.c
index c5f458b9..4119ad79 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -558,11 +558,44 @@ pr_register_active_paths(struct multipath *mpp)
 	}
 }
 
+static void
+save_offline_paths(const struct multipath *mpp, vector offline_paths)
+{
+	unsigned int i, j;
+	struct path *pp;
+	struct pathgroup *pgp;
+
+	vector_foreach_slot (mpp->pg, pgp, i)
+		vector_foreach_slot (pgp->paths, pp, j)
+			if (pp->initialized == INIT_OK && pp->offline)
+				/* ignore failures storing the paths. */
+				store_path(offline_paths, pp);
+}
+
+static void
+handle_orphaned_offline_paths(vector offline_paths)
+{
+	unsigned int i;
+	struct path *pp;
+
+	vector_foreach_slot (offline_paths, pp, i)
+		if (pp->mpp == NULL)
+			pp->add_when_online = true;
+}
+
+static void
+cleanup_reset_vec(struct _vector **v)
+{
+	vector_reset(*v);
+}
+
 static int
 update_map (struct multipath *mpp, struct vectors *vecs, int new_map)
 {
 	int retries = 3;
 	char *params __attribute__((cleanup(cleanup_charp))) = NULL;
+	struct _vector offline_paths_vec = { .allocated = 0 };
+	vector offline_paths __attribute__((cleanup(cleanup_reset_vec))) = &offline_paths_vec;
 
 retry:
 	condlog(4, "%s: updating new map", mpp->alias);
@@ -599,6 +632,9 @@ fail:
 		return 1;
 	}
 
+	if (new_map && retries < 0)
+		save_offline_paths(mpp, offline_paths);
+
 	if (setup_multipath(vecs, mpp))
 		return 1;
 
@@ -609,6 +645,9 @@ fail:
 	if (mpp->prflag == PRFLAG_SET)
 		pr_register_active_paths(mpp);
 
+	if (VECTOR_SIZE(offline_paths) != 0)
+		handle_orphaned_offline_paths(offline_paths);
+
 	if (retries < 0)
 		condlog(0, "%s: failed reload in new map update", mpp->alias);
 	return 0;
@@ -2253,7 +2292,8 @@ check_path (struct vectors * vecs, struct path * pp, unsigned int ticks)
 	int ret;
 
 	if (((pp->initialized == INIT_OK ||
-	      pp->initialized == INIT_REQUESTED_UDEV) && !pp->mpp) ||
+	      pp->initialized == INIT_REQUESTED_UDEV) && !pp->mpp &&
+	      !pp->add_when_online) ||
 	    pp->initialized == INIT_REMOVED)
 		return 0;
 
@@ -2367,6 +2407,17 @@ check_path (struct vectors * vecs, struct path * pp, unsigned int ticks)
 				 */
 				pp->checkint = max_checkint;
 			}
+		} else if (pp->initialized == INIT_OK && pp->add_when_online &&
+			   (newstate == PATH_UP || newstate == PATH_GHOST)) {
+			pp->add_when_online = false;
+			if (can_recheck_wwid(pp) &&
+			    check_path_wwid_change(pp)) {
+				condlog(0, "%s: path wwid change detected. Removing", pp->dev);
+				handle_path_wwid_change(pp, vecs);
+				return 0;
+			}
+			ev_add_path(pp, vecs, 1);
+			pp->tick = 1;
 		}
 		return 0;
 	}
diff --git a/multipathd/multipathd.8 b/multipathd/multipathd.8
index d3aa7a73..2ed036d4 100644
--- a/multipathd/multipathd.8
+++ b/multipathd/multipathd.8
@@ -529,7 +529,9 @@ The device serial number.
 The device marginal state, either \fImarginal\fR or \fInormal\fR.
 .TP
 .B %m
-The multipath device that this device is a path of.
+The multipath device that this device is a path of, or \fI[offline]\fR
+if this device could not be added to a device because it is offline or
+\fI[orphan]\fR if it is not part of any multipath device.
 .TP
 .B %N
 The host World Wide Node Name (WWNN) of the device.