device-mapper-multipath/0064-libmpathpersist-update-reservation-key-before-checki.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Fri, 25 Jul 2025 23:58:53 -0400
Subject: [PATCH] libmpathpersist: update reservation key before checking paths

There is a race condition when changing reservation keys where a failed
path could come back online after libmpathpersist checks the paths, but
before it updates the reservation key. In this case, the path would come
up and get reregistered with the old key by multipathd, and
libmpathpersist would not update its key, because the path was down
when it checked.

To fix this, check the paths after updating the key, so any path that
comes up after getting checked will use the updated key.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmpathpersist/mpath_persist_int.c | 80 ++++++++++++-----------------
 1 file changed, 34 insertions(+), 46 deletions(-)

diff --git a/libmpathpersist/mpath_persist_int.c b/libmpathpersist/mpath_persist_int.c
index 302bebc2..d498e69e 100644
--- a/libmpathpersist/mpath_persist_int.c
+++ b/libmpathpersist/mpath_persist_int.c
@@ -110,39 +110,18 @@ void *mpath_alloc_prin_response(int prin_sa)
 	return ptr;
 }
 
-static int get_mpvec(vector curmp, vector pathvec, char *refwwid)
+static int get_path_info(struct multipath *mpp, vector pathvec)
 {
-	int i;
-	struct multipath *mpp;
-
-	vector_foreach_slot (curmp, mpp, i){
-		/*
-		 * discard out of scope maps
-		 */
-		if (!mpp->alias) {
-			condlog(0, "%s: map with empty alias!", __func__);
-			continue;
-		}
-
-		if (mpp->pg != NULL)
-			/* Already seen this one */
-			continue;
-
-		if (refwwid && strncmp (mpp->alias, refwwid, WWID_SIZE - 1))
-			continue;
-
-		if (update_multipath_table(mpp, pathvec, DI_CHECKER) != DMP_OK ||
-		    update_mpp_paths(mpp, pathvec)) {
-			condlog(1, "error parsing map %s", mpp->wwid);
-			remove_map(mpp, pathvec, curmp);
-			i--;
-		} else
-			extract_hwe_from_path(mpp);
+	if (update_multipath_table(mpp, pathvec, DI_CHECKER) != DMP_OK ||
+	    update_mpp_paths(mpp, pathvec)) {
+		condlog(0, "error parsing map %s", mpp->wwid);
+		return MPATH_PR_DMMP_ERROR;
 	}
+	extract_hwe_from_path(mpp);
 	return MPATH_PR_SUCCESS ;
 }
 
-static int mpath_get_map(vector curmp, vector pathvec, int fd, char **palias,
+static int mpath_get_map(vector curmp, int fd, char **palias,
 			 struct multipath **pmpp)
 {
 	int ret = MPATH_PR_DMMP_ERROR;
@@ -178,12 +157,6 @@ static int mpath_get_map(vector curmp, vector pathvec, int fd, char **palias,
 		goto out;
 	}
 
-	/* get info of all paths from the dm device     */
-	if (get_mpvec(curmp, pathvec, alias)){
-		condlog(0, "%s: failed to get device info.", alias);
-		goto out;
-	}
-
 	mpp = find_mp_by_alias(curmp, alias);
 
 	if (!mpp) {
@@ -210,7 +183,11 @@ int do_mpath_persistent_reserve_in(vector curmp, vector pathvec,
 	struct multipath *mpp;
 	int ret;
 
-	ret = mpath_get_map(curmp, pathvec, fd, NULL, &mpp);
+	ret = mpath_get_map(curmp, fd, NULL, &mpp);
+	if (ret != MPATH_PR_SUCCESS)
+		return ret;
+
+	ret = get_path_info(mpp, pathvec);
 	if (ret != MPATH_PR_SUCCESS)
 		return ret;
 
@@ -747,24 +724,14 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd,
 	bool unregistering, preempting_reservation = false;
 	bool updated_prkey = false;
 
-	ret = mpath_get_map(curmp, pathvec, fd, &alias, &mpp);
+	ret = mpath_get_map(curmp, fd, &alias, &mpp);
 	if (ret != MPATH_PR_SUCCESS)
 		return ret;
 
 	conf = get_multipath_config();
 	select_reservation_key(conf, mpp);
-	select_all_tg_pt(conf, mpp);
-	/*
-	 * If a device preempts itself, it will need to suspend and resume.
-	 * Set mpp->skip_kpartx to make sure we set the flags to skip kpartx
-	 * if necessary, when doing this.
-	 */
-	select_skip_kpartx(conf, mpp);
 	put_multipath_config(conf);
 
-	if (rq_servact == MPATH_PROUT_REG_IGN_SA)
-		set_ignored_key(mpp, paramp->key);
-
 	unregistering = (memcmp(&zerokey, paramp->sa_key, 8) == 0);
 	if (mpp->prkey_source == PRKEY_SOURCE_FILE &&
 	    (rq_servact == MPATH_PROUT_REG_IGN_SA ||
@@ -822,6 +789,27 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd,
 		}
 	}
 
+	ret = get_path_info(mpp, pathvec);
+	if (ret != MPATH_PR_SUCCESS) {
+		if (updated_prkey)
+			update_prkey_flags(alias, get_be64(oldkey),
+					   mpp->sa_flags);
+		goto out1;
+	}
+
+	conf = get_multipath_config();
+	select_all_tg_pt(conf, mpp);
+	/*
+	 * If a device preempts itself, it will need to suspend and resume.
+	 * Set mpp->skip_kpartx to make sure we set the flags to skip kpartx
+	 * if necessary, when doing this.
+	 */
+	select_skip_kpartx(conf, mpp);
+	put_multipath_config(conf);
+
+	if (rq_servact == MPATH_PROUT_REG_IGN_SA)
+		set_ignored_key(mpp, paramp->key);
+
 	switch(rq_servact)
 	{
 	case MPATH_PROUT_REG_SA: