From 6f56f0c4f1241f1694a6a9438dd4f78d4513a917 Mon Sep 17 00:00:00 2001 From: Yu Kuai Date: Mon, 29 May 2023 21:20:34 +0800 Subject: md: add a mutex to synchronize idle and frozen in action_store() 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 Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230529132037.2124527-4-yukuai1@huaweicloud.com --- drivers/md/md.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/md/md.h') diff --git a/drivers/md/md.h b/drivers/md/md.h index 1aef86bf3fc3..18c168bf5fab 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -535,6 +535,9 @@ struct mddev { */ struct list_head deleting; + /* 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; -- cgit v1.2.3