Hi, 在 2023/06/13 22:43, Xiao Ni 写道:
在 2023/5/29 下午9:20, Yu Kuai 写道:From: Yu Kuai <yukuai3@xxxxxxxxxx> Currently, for idle and frozen, action_store will hold 'reconfig_mutex' and call md_reap_sync_thread() to stop sync thread, however, this will cause deadlock (explained in the next patch). In order to fix the problem, following patch will release 'reconfig_mutex' and wait on 'resync_wait', like md_set_readonly() and do_md_stop() does. Consider that action_store() will set/clear 'MD_RECOVERY_FROZEN' unconditionally, which might cause unexpected problems, for example, frozen just set 'MD_RECOVERY_FROZEN' and is still in progress, while 'idle' clear 'MD_RECOVERY_FROZEN' and new sync thread is started, which might starve in progress frozen. A mutex is added to synchronize idle and frozen from action_store(). Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- drivers/md/md.c | 5 +++++ drivers/md/md.h | 3 +++ 2 files changed, 8 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 23e8e7eae062..63a993b52cd7 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -644,6 +644,7 @@ void mddev_init(struct mddev *mddev) mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); mutex_init(&mddev->delete_mutex); + mutex_init(&mddev->sync_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->all_mddevs); @@ -4785,14 +4786,18 @@ static void stop_sync_thread(struct mddev *mddev) static void idle_sync_thread(struct mddev *mddev) { + mutex_lock(&mddev->sync_mutex); clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); stop_sync_thread(mddev); + mutex_unlock(&mddev->sync_mutex); } static void frozen_sync_thread(struct mddev *mddev) { + mutex_init(&mddev->delete_mutex);typo error? It should be mutex_lock(&mddev->sync_mutex); ?
Yes, and thanks for spotting this, this looks like I did this while rebasing. Thanks, Kuai
Regards Xiaoset_bit(MD_RECOVERY_FROZEN, &mddev->recovery); stop_sync_thread(mddev); + mutex_unlock(&mddev->sync_mutex); } static ssize_t diff --git a/drivers/md/md.h b/drivers/md/md.h index bfd2306bc750..2fa903de5bd0 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -537,6 +537,9 @@ struct mddev { /* Protect the deleting list */ struct mutex delete_mutex; + /* Used to synchronize idle and frozen for action_store() */ + struct mutex sync_mutex; + bool has_superblocks:1; bool fail_last_dev:1; bool serialize_policy:1;.
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