md: Don't clear MD_CLOSING until mddev is freed

JIRA: https://issues.redhat.com/browse/RHEL-94433
JIRA: https://issues.redhat.com/browse/RHEL-20191
JIRA: https://issues.redhat.com/browse/RHEL-9656

commit 5f286f3
Author: Xiao Ni <xni@redhat.com>
Date:   Wed Jun 11 15:31:07 2025 +0800

    md: Don't clear MD_CLOSING until mddev is freed

    UNTIL_STOP is used to avoid mddev is freed on the last close before adding
    disks to mddev. And it should be cleared when stopping an array which is
    mentioned in commit efeb53c ("md: Allow md devices to be created by
    name."). So reset ->hold_active to 0 in md_clean.

    And MD_CLOSING should be kept until mddev is freed to avoid reopen.

    Reviewed-by: Yu Kuai <yukuai3@huawei.com>
    Signed-off-by: Xiao Ni <xni@redhat.com>
    Link: https://lore.kernel.org/linux-raid/20250611073108.25463-3-xni@redhat.com
    Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Signed-off-by: Nigel Croxon <ncroxon@redhat.com>

Author: ncroxon

drivers/md/md.c

@@ -6451,15 +6451,10 @@ static void md_clean(struct mddev *mddev)
 	mddev->persistent = 0;
 	mddev->level = LEVEL_NONE;
 	mddev->clevel[0] = 0;
-	/*
-	 * Don't clear MD_CLOSING, or mddev can be opened again.
-	 * 'hold_active != 0' means mddev is still in the creation
-	 * process and will be used later.
-	 */
-	if (mddev->hold_active)
-		mddev->flags = 0;
-	else
-		mddev->flags &= BIT_ULL_MASK(MD_CLOSING);
+	/* if UNTIL_STOP is set, it's cleared here */
+	mddev->hold_active = 0;
+	/* Don't clear MD_CLOSING, or mddev can be opened again. */
+	mddev->flags &= BIT_ULL_MASK(MD_CLOSING);
 	mddev->sb_flags = 0;
 	mddev->ro = MD_RDWR;
 	mddev->metadata_type[0] = 0;
@@ -6686,9 +6681,6 @@ static int do_md_stop(struct mddev *mddev, int mode)
 		export_array(mddev);
 		md_clean(mddev);
 		set_bit(MD_DELETED, &mddev->flags);
-
-		if (mddev->hold_active == UNTIL_STOP)
-			mddev->hold_active = 0;
 	}
 	md_new_event();
 	sysfs_notify_dirent_safe(mddev->sysfs_state);