From 64e5e09afc14f8cc9058b0ed5c9cc4c8cd126b85 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Mon, 29 May 2023 21:20:33 +0800 Subject: [PATCH] md: refactor action_store() for 'idle' and 'frozen' 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. Signed-off-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230529132037.2124527-3-yukuai1@huaweicloud.com --- 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 d445d5f..7fa91f0 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4747,6 +4747,46 @@ 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) { @@ -4754,22 +4794,11 @@ 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); -- 2.7.4