linux-kernel - [PATCH 3/5] md: make sure md_do_sync() will set MD_RECOVERY

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Message-Id: <20240120103734.4155446-4-yukuai1@huaweicloud.com>
Date: Sat, 20 Jan 2024 18:37:32 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: mpatocka@...hat.com,
	dm-devel@...ts.linux.dev,
	msnitzer@...hat.com,
	heinzm@...hat.com,
	song@...nel.org,
	yukuai3@...wei.com
Cc: linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	yukuai1@...weicloud.com,
	yi.zhang@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH 3/5] md: make sure md_do_sync() will set MD_RECOVERY_DONE

From: Yu Kuai <yukuai3@...wei.com>

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().

Before this patch, if MD_RECOVERY_WAIT is set or the array is read-only,
md_do_sync() will return without setting MD_RECOVERY_DONE, hence use
stop_sync_thread() directly will hang because md_check_recovery() can't
clear MD_RECOVERY_RUNNING, which is possible for dm-raid.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 drivers/md/md.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6906d023f1d6..ba45c7be3dbe 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8788,12 +8788,13 @@ 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_WAIT, &mddev->recovery) ||
+	    !md_is_rdwr(mddev)) {/* never try to sync a read-only array */
 		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-		return;
+		goto out;
 	}
 
 	if (mddev_is_clustered(mddev)) {
@@ -9171,6 +9172,7 @@ void md_do_sync(struct md_thread *thread)
 						mddev->array_sectors);
 	}
 
+out:
 	spin_lock(&mddev->lock);
 	if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 		/* We completed so min/max setting can be forgotten if used. */
-- 
2.39.2