device-mapper-multipath/0065-libmpathpersist-retry-on-conflicts-in-mpath_prout_co.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Fri, 25 Jul 2025 23:58:54 -0400
Subject: [PATCH] libmpathpersist: retry on conflicts in mpath_prout_common

mpath_prout_common() just needs to execute a prout command down one
path. If it uses a path that was down when the key was changed and has
since been restored, but multipathd hasn't noticed yet, that path will
still be using the old key. This was causing mpath_prout_common() to
fail with MPATH_PR_RESERV_CONFLICT, even if there were other paths that
would work.

Now, if prout command fails with MPATH_PR_RESERV_CONFLICT,
mpath_prout_common() checks if pp->dmstate is PSTATE_FAILED. If it is,
mpath_prout_common() assumes that multipathd has not yet noticed that
the path is back online and it might still have and old key, so it
doesn't immediately return. If it can't successfully send the command
down another path, it will still return MPATH_PR_RESERV_CONFLICT.

Also, make sure prout_do_scsi_ioctl() always returns a MPATH_PR_*
type error.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
---
 libmpathpersist/mpath_persist_int.c | 14 +++++++++++++-
 libmpathpersist/mpath_pr_ioctl.c    |  2 +-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/libmpathpersist/mpath_persist_int.c b/libmpathpersist/mpath_persist_int.c
index d498e69e..762958e8 100644
--- a/libmpathpersist/mpath_persist_int.c
+++ b/libmpathpersist/mpath_persist_int.c
@@ -216,6 +216,7 @@ mpath_prout_common(struct multipath *mpp, int rq_servact, int rq_scope,
 	struct pathgroup *pgp = NULL;
 	struct path *pp = NULL;
 	bool found = false;
+	bool conflict = false;
 
 	vector_foreach_slot (mpp->pg, pgp, j) {
 		vector_foreach_slot (pgp->paths, pp, i) {
@@ -232,12 +233,23 @@ mpath_prout_common(struct multipath *mpp, int rq_servact, int rq_scope,
 						  rq_type, paramp, noisy);
 			if (ret == MPATH_PR_SUCCESS && pptr)
 				*pptr = pp;
+			/*
+			 * If this path is considered down by the kernel,
+			 * it may have just come back up, and multipathd
+			 * may not have had time to update the key. Allow
+			 * reservation conflicts.
+			 */
+			if (ret == MPATH_PR_RESERV_CONFLICT &&
+			    pp->dmstate == PSTATE_FAILED) {
+				conflict = true;
+				continue;
+			}
 			if (ret != MPATH_PR_RETRYABLE_ERROR)
 				return ret;
 		}
 	}
 	if (found)
-		return MPATH_PR_OTHER;
+		return conflict ? MPATH_PR_RESERV_CONFLICT : MPATH_PR_OTHER;
 	condlog(0, "%s: no path available", mpp->wwid);
 	return MPATH_PR_DMMP_ERROR;
 }
diff --git a/libmpathpersist/mpath_pr_ioctl.c b/libmpathpersist/mpath_pr_ioctl.c
index dfdbbb65..6eaec7cd 100644
--- a/libmpathpersist/mpath_pr_ioctl.c
+++ b/libmpathpersist/mpath_pr_ioctl.c
@@ -103,7 +103,7 @@ retry :
 	{
 		condlog(0, "%s: ioctl failed %d", dev, ret);
 		close(fd);
-		return ret;
+		return MPATH_PR_OTHER;
 	}
 
 	condlog(4, "%s: Duration=%u (ms)", dev, io_hdr.duration);