iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

md: add a mutex to synchronize idle and frozen in action_store()

Browse Source 
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
This commit is contained in:
Yu Kuai 2023-05-29 21:20:34 +08:00 committed by Song Liu
parent 64e5e09afc
commit 6f56f0c4f1
2 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/md/md.c
View File

@ -643,6 +643,7 @@ void mddev_init(struct mddev *mddev)
{ {
mutex_init(&mddev->open_mutex); mutex_init(&mddev->open_mutex);
mutex_init(&mddev->reconfig_mutex); mutex_init(&mddev->reconfig_mutex);
mutex_init(&mddev->sync_mutex);
mutex_init(&mddev->bitmap_info.mutex); mutex_init(&mddev->bitmap_info.mutex);
INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->disks);
INIT_LIST_HEAD(&mddev->all_mddevs); 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) static void idle_sync_thread(struct mddev *mddev)
{ {
mutex_lock(&mddev->sync_mutex);
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
stop_sync_thread(mddev); stop_sync_thread(mddev);
mutex_unlock(&mddev->sync_mutex);
} }
static void frozen_sync_thread(struct mddev *mddev) static void frozen_sync_thread(struct mddev *mddev)
{ {
mutex_lock(&mddev->sync_mutex);
set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
stop_sync_thread(mddev); stop_sync_thread(mddev);
mutex_unlock(&mddev->sync_mutex);
} }
static ssize_t static ssize_t

3
drivers/md/md.h
View File

@ -535,6 +535,9 @@ struct mddev {
*/ */
struct list_head deleting; struct list_head deleting;
/* Used to synchronize idle and frozen for action_store() */
struct mutex sync_mutex;
bool has_superblocks:1; bool has_superblocks:1;
bool fail_last_dev:1; bool fail_last_dev:1;
bool serialize_policy:1; bool serialize_policy:1;