Received-SPF: pass (google.com: domain of linux-kernel+bounces-36694-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
From: Yu Kuai <yukuai3@huawei.com>
To: <agk@redhat.com>, <snitzer@kernel.org>, <mpatocka@redhat.com>,
	<dm-devel@lists.linux.dev>, <xni@redhat.com>, <song@kernel.org>,
	<yukuai3@huawei.com>, <jbrassow@f14.redhat.com>, <neilb@suse.de>,
	<heinzm@redhat.com>, <shli@fb.com>, <akpm@osdl.org>
CC: <linux-kernel@vger.kernel.org>, <linux-raid@vger.kernel.org>,
	<yukuai1@huaweicloud.com>, <yi.zhang@huawei.com>, <yangerkun@huawei.com>
Subject: [PATCH v2 03/11] md: make sure md_do_sync() will set MD_RECOVERY_DONE
Date: Wed, 24 Jan 2024 17:14:13 +0800
Message-ID: <20240124091421.1261579-4-yukuai3@huawei.com>
In-Reply-To: <20240124091421.1261579-1-yukuai3@huawei.com>
References: <20240124091421.1261579-1-yukuai3@huawei.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain

stop_sync_thread() will interrupt md_do_sync(), and md_do_sync() must
set MD_RECOVERY_DONE, so that follow up md_check_recovery() will
unregister sync_thread, clear MD_RECOVERY_RUNNING and wake up
stop_sync_thread().

If MD_RECOVERY_WAIT is set or the array is read-only, md_do_sync() will
return without setting MD_RECOVERY_DONE, and after commit f52f5c71f3d4
("md: fix stopping sync thread"), dm-raid switch from
md_reap_sync_thread() to stop_sync_thread() to unregister sync_thread
from md_stop() and md_stop_writes(), causing the test
shell/lvconvert-raid-reshape.sh hang.

We shouldn't switch back to md_reap_sync_thread() because it's
problematic in the first place. Fix the problem by making sure
md_do_sync() will set MD_RECOVERY_DONE.

Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Closes: https://lore.kernel.org/all/ece2b06f-d647-6613-a534-ff4c9bec1142@redhat.com/
Fixes: d5d885fd514f ("md: introduce new personality funciton start()")
Fixes: 5fd6c1dce06e ("[PATCH] md: allow checkpoint of recovery with version-1 superblock")
Fixes: f52f5c71f3d4 ("md: fix stopping sync thread")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/md.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6906d023f1d6..c65dfd156090 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8788,12 +8788,16 @@ void md_do_sync(struct md_thread *thread)
 	int ret;
 
 	/* just incase thread restarts... */
-	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
-	    test_bit(MD_RECOVERY_WAIT, &mddev->recovery))
+	if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
 		return;
-	if (!md_is_rdwr(mddev)) {/* never try to sync a read-only array */
+
+	if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+		goto skip;
+
+	if (test_bit(MD_RECOVERY_WAIT, &mddev->recovery) ||
+	    !md_is_rdwr(mddev)) {/* never try to sync a read-only array */
 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-		return;
+		goto skip;
 	}
 
 	if (mddev_is_clustered(mddev)) {
-- 
2.39.2