device-mapper-multipath/0071-libmpathpersist-handle-preempting-all-registrants-re.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Wed, 10 Sep 2025 17:52:12 -0400
Subject: [PATCH] libmpathpersist: handle preempting all registrants
 reservations

All Registrants reservations (types 7 and 8) are held by key 0x0. When
preempting one, all registrations are cleared, except for the one on the
path that issued the PREEMPT. libmpathpersist needs to handle this just
like the other cases of self-preemption, so that all the paths of the
preempting multipath device have their registrations restored while the
device is suspended.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmpathpersist/mpath_persist_int.c | 31 +++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/libmpathpersist/mpath_persist_int.c b/libmpathpersist/mpath_persist_int.c
index da8a0d04..87d7cb6b 100644
--- a/libmpathpersist/mpath_persist_int.c
+++ b/libmpathpersist/mpath_persist_int.c
@@ -579,8 +579,9 @@ static int mpath_prout_reg(struct multipath *mpp,int rq_servact, int rq_scope,
  * is suspended before issuing the preemption, and the keys are reregistered
  * before resuming it.
  */
-static int preempt_self(struct multipath *mpp, int rq_servact, int rq_scope,
-			unsigned int rq_type, int noisy, bool do_release)
+static int do_preempt_self(struct multipath *mpp, struct be64 sa_key,
+			   int rq_servact, int rq_scope, unsigned int rq_type,
+			   int noisy, bool do_release)
 {
 	int status, rel_status = MPATH_PR_SUCCESS;
 	struct path *pp = NULL;
@@ -593,7 +594,7 @@ static int preempt_self(struct multipath *mpp, int rq_servact, int rq_scope,
 	}
 
 	memcpy(paramp.key, &mpp->reservation_key, 8);
-	memcpy(paramp.sa_key, &mpp->reservation_key, 8);
+	memcpy(paramp.sa_key, &sa_key, 8);
 	status = mpath_prout_common(mpp, rq_servact, rq_scope, rq_type,
 				    &paramp, noisy, &pp);
 	if (status != MPATH_PR_SUCCESS) {
@@ -629,6 +630,21 @@ fail_resume:
 	return (rel_status != MPATH_PR_SUCCESS) ? rel_status : status;
 }
 
+static int preempt_self(struct multipath *mpp, int rq_servact, int rq_scope,
+			unsigned int rq_type, int noisy, bool do_release)
+{
+	return do_preempt_self(mpp, mpp->reservation_key, rq_servact, rq_scope,
+			       rq_type, noisy, do_release);
+}
+
+static int preempt_all(struct multipath *mpp, int rq_servact, int rq_scope,
+		       unsigned int rq_type, int noisy)
+{
+	struct be64 zerokey = {0};
+	return do_preempt_self(mpp, zerokey, rq_servact, rq_scope, rq_type,
+			       noisy, false);
+}
+
 static int mpath_prout_rel(struct multipath *mpp,int rq_servact, int rq_scope,
 			   unsigned int rq_type,
 			   struct prout_param_descriptor * paramp, int noisy)
@@ -904,8 +920,15 @@ int do_mpath_persistent_reserve_out(vector curmp, vector pathvec, int fd,
 		break;
 	case MPATH_PROUT_PREE_SA:
 	case MPATH_PROUT_PREE_AB_SA:
-		if (reservation_key_matches(mpp, paramp->sa_key, noisy) == YNU_YES)
+		if (reservation_key_matches(mpp, paramp->sa_key, noisy) == YNU_YES) {
 			preempting_reservation = true;
+			if (memcmp(paramp->sa_key, &zerokey, 8) == 0) {
+				/* all registrants case */
+				ret = preempt_all(mpp, rq_servact, rq_scope,
+						  rq_type, noisy);
+				break;
+			}
+		}
 		/* if we are preempting ourself */
 		if (memcmp(paramp->sa_key, paramp->key, 8) == 0) {
 			ret = preempt_self(mpp, rq_servact, rq_scope, rq_type,