在 2023/5/29 下午9:20, Yu Kuai 写道:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
Prepare to handle 'idle' and 'frozen' differently to fix a deadlock, there
are no functional changes except that MD_RECOVERY_RUNNING is checked
again after 'reconfig_mutex' is held.
Can you explain more about why it needs to check MD_RECOVERY_RUNNING
again here?
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md.c | 61 ++++++++++++++++++++++++++++++++++++-------------
1 file changed, 45 insertions(+), 16 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9b97731e1fe4..23e8e7eae062 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4755,6 +4755,46 @@ action_show(struct mddev *mddev, char *page)
return sprintf(page, "%s\n", type);
}
+static void stop_sync_thread(struct mddev *mddev)
+{
+ if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ return;
+
+ if (mddev_lock(mddev))
+ return;
+
+ /*
+ * Check again in case MD_RECOVERY_RUNNING is cleared before lock is
+ * held.
+ */
+ if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
+ mddev_unlock(mddev);
+ return;
+ }
+
+ if (work_pending(&mddev->del_work))
+ flush_workqueue(md_misc_wq);
+
+ if (mddev->sync_thread) {
+ set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+ md_reap_sync_thread(mddev);
+ }
+
+ mddev_unlock(mddev);
+}
+
+static void idle_sync_thread(struct mddev *mddev)
+{
+ clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ stop_sync_thread(mddev);
+}
+
+static void frozen_sync_thread(struct mddev *mddev)
+{
+ set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ stop_sync_thread(mddev);
+}
+
static ssize_t
action_store(struct mddev *mddev, const char *page, size_t len)
{
@@ -4762,22 +4802,11 @@ action_store(struct mddev *mddev, const char *page, size_t len)
return -EINVAL;
- if (cmd_match(page, "idle") || cmd_match(page, "frozen")) {
- if (cmd_match(page, "frozen"))
- set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- else
- clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) &&
- mddev_lock(mddev) == 0) {
- if (work_pending(&mddev->del_work))
- flush_workqueue(md_misc_wq);
- if (mddev->sync_thread) {
- set_bit(MD_RECOVERY_INTR, &mddev->recovery);
- md_reap_sync_thread(mddev);
- }
- mddev_unlock(mddev);
- }
- } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+ if (cmd_match(page, "idle"))
+ idle_sync_thread(mddev);
+ else if (cmd_match(page, "frozen"))
+ frozen_sync_thread(mddev);
+ else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
else if (cmd_match(page, "resync"))
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
--
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