device-mapper-multipath/0101-multipathd-Make-sure-to-disable-queueing-if-recovery.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Wed, 22 Nov 2023 16:41:22 -0500
Subject: [PATCH] multipathd: Make sure to disable queueing if recovery has
 failed.

If a multipath device has no_path_retry set to a number and has lost all
paths, gone into recovery mode, and timed out, it will disable
queue_if_no_paths. After that, if the device is reloaded by multipath
outside of multipathd, it will re-enable queuieng on the device. When
multipathd later calls set_no_path_retry() to update the queueing state,
it will not disable queue_if_no_paths, since the device is still in the
recovery state, so it believes no work needs to be done. The device will
remain in the recovery state, with retry_ticks at 0, and queueing
enabled, even though there are no usable paths.

To fix this, in set_no_path_retry(), if no_path_retry is set to a number
and the device is queueing but it is in recovery mode and out of
retries with no usable paths, manually disable queue_if_no_path.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/structs_vec.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index 4a32b405..86ad89ca 100644
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -614,8 +614,19 @@ void __set_no_path_retry(struct multipath *mpp, bool check_features)
 			    !mpp->in_recovery)
 				dm_queue_if_no_path(mpp->alias, 1);
 			leave_recovery_mode(mpp);
-		} else
-			enter_recovery_mode(mpp);
+		} else {
+			/*
+			 * If in_recovery is set, enter_recovery_mode does
+			 * nothing. If the device is already in recovery
+			 * mode and has already timed out, manually call
+			 * dm_queue_if_no_path to stop it from queueing.
+			 */
+			if ((!check_features || is_queueing) &&
+			    mpp->in_recovery && mpp->retry_tick == 0)
+				dm_queue_if_no_path(mpp->alias, 0);
+			if (pathcount(mpp, PATH_PENDING) == 0)
+				enter_recovery_mode(mpp);
+		}
 		break;
 	}
 }
@@ -761,6 +772,11 @@ int verify_paths(struct multipath *mpp)
  *   -1 (FAIL)  : fail_if_no_path
  *    0 (UNDEF) : nothing
  *   >0         : queue_if_no_path enabled, turned off after polling n times
+ *
+ * Since this will only be called when fail_path(), update_multipath(), or
+ * io_err_stat_handle_pathfail() are failing a previously active path, the
+ * device cannot already be in recovery mode, so there will never be a need
+ * to disable queueing here.
  */
 void update_queue_mode_del_path(struct multipath *mpp)
 {
@@ -774,6 +790,12 @@ void update_queue_mode_del_path(struct multipath *mpp)
 	condlog(2, "%s: remaining active paths: %d", mpp->alias, active);
 }
 
+/*
+ * Since this will only be called from check_path() -> reinstate_path() after
+ * the queueing state has been updated in set_no_path_retry, this does not
+ * need to worry about modifying the queueing state except when actually
+ * leaving recovery mode.
+ */
 void update_queue_mode_add_path(struct multipath *mpp)
 {
 	int active = count_active_paths(mpp);