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| author | Yu Kuai <yukuai3@huawei.com> | 2023-05-29 16:20:34 +0300 |
|---|---|---|
| committer | Song Liu <song@kernel.org> | 2023-07-27 10:13:28 +0300 |
| commit | 6f56f0c4f1241f1694a6a9438dd4f78d4513a917 (patch) | |
| tree | 3b41e3b51cf8e5c1c21a056103722137c6e367e8 /drivers | |
| parent | 64e5e09afc14f8cc9058b0ed5c9cc4c8cd126b85 (diff) | |
| download | linux-6f56f0c4f1241f1694a6a9438dd4f78d4513a917.tar.xz | |
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 <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230529132037.2124527-4-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/md.c | 5 | ||||
| -rw-r--r-- | drivers/md/md.h | 3 |
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 7fa91f0e5620..3d7e87cab8ad 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -643,6 +643,7 @@ void mddev_init(struct mddev *mddev) { mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); + mutex_init(&mddev->sync_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->all_mddevs); @@ -4777,14 +4778,18 @@ 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_lock(&mddev->sync_mutex); set_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 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; |