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md: don't fail action_store() if sync_thread is not registered

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MD_RECOVERY_RUNNING will always be set when trying to register a new
sync_thread, however, if md_start_sync() turns out to do nothing,
MD_RECOVERY_RUNNING will be cleared in this case. And during the race
window, action_store() will return -EBUSY, which will cause some
mdadm tests to fail. For example:

The test 07reshape5intr will add a new disk to array, then start
reshape:

mdadm /dev/md0 --add /dev/xxx
mdadm --grow /dev/md0 -n 3

And add_bound_rdev() from mdadm --add will set MD_RECOVERY_NEEDED,
then during the race windown, mdadm --grow will fail.

Fix the problem by waiting in action_store() during the race window,
fail only if sync_thread is registered.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240611132251.1967786-8-yukuai1@huaweicloud.com
This commit is contained in:
Yu Kuai
2024-06-11 21:22:46 +08:00
committed by Song Liu
parent df79234bdc
commit 5ce10a3859
2 changed files with 33 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/md/md.c
+33 -52
View File
@@ -753,7 +753,6 @@ int mddev_init(struct mddev *mddev)
mutex_init(&mddev->open_mutex);
mutex_init(&mddev->reconfig_mutex);
mutex_init(&mddev->sync_mutex);
mutex_init(&mddev->suspend_mutex);
mutex_init(&mddev->bitmap_info.mutex);
INIT_LIST_HEAD(&mddev->disks);
@@ -5021,34 +5020,6 @@ void md_unfrozen_sync_thread(struct mddev *mddev)
}
EXPORT_SYMBOL_GPL(md_unfrozen_sync_thread);
static void idle_sync_thread(struct mddev *mddev)
{
mutex_lock(&mddev->sync_mutex);
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
if (mddev_lock(mddev)) {
mutex_unlock(&mddev->sync_mutex);
return;
}
stop_sync_thread(mddev, false);
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);
if (mddev_lock(mddev)) {
mutex_unlock(&mddev->sync_mutex);
return;
}
stop_sync_thread(mddev, false);
mutex_unlock(&mddev->sync_mutex);
}
static int mddev_start_reshape(struct mddev *mddev)
{
int ret;
@@ -5056,24 +5027,13 @@ static int mddev_start_reshape(struct mddev *mddev)
if (mddev->pers->start_reshape == NULL)
return -EINVAL;
ret = mddev_lock(mddev);
if (ret)
return ret;
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
mddev_unlock(mddev);
return -EBUSY;
}
if (mddev->reshape_position == MaxSector ||
mddev->pers->check_reshape == NULL ||
mddev->pers->check_reshape(mddev)) {
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
ret = mddev->pers->start_reshape(mddev);
if (ret) {
mddev_unlock(mddev);
if (ret)
return ret;
}
} else {
/*
* If reshape is still in progress, and md_check_recovery() can
@@ -5083,7 +5043,6 @@ static int mddev_start_reshape(struct mddev *mddev)
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
}
mddev_unlock(mddev);
sysfs_notify_dirent_safe(mddev->sysfs_degraded);
return 0;
}
@@ -5097,36 +5056,53 @@ action_store(struct mddev *mddev, const char *page, size_t len)
if (!mddev->pers || !mddev->pers->sync_request)
return -EINVAL;
retry:
if (work_busy(&mddev->sync_work))
flush_work(&mddev->sync_work);
ret = mddev_lock(mddev);
if (ret)
return ret;
if (work_busy(&mddev->sync_work)) {
mddev_unlock(mddev);
goto retry;
}
action = md_sync_action_by_name(page);
/* TODO: mdadm rely on "idle" to start sync_thread. */
if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
switch (action) {
case ACTION_FROZEN:
frozen_sync_thread(mddev);
return len;
md_frozen_sync_thread(mddev);
ret = len;
goto out;
case ACTION_IDLE:
idle_sync_thread(mddev);
md_idle_sync_thread(mddev);
break;
case ACTION_RESHAPE:
case ACTION_RECOVER:
case ACTION_CHECK:
case ACTION_REPAIR:
case ACTION_RESYNC:
return -EBUSY;
ret = -EBUSY;
goto out;
default:
return -EINVAL;
ret = -EINVAL;
goto out;
}
} else {
switch (action) {
case ACTION_FROZEN:
set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
return len;
ret = len;
goto out;
case ACTION_RESHAPE:
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
ret = mddev_start_reshape(mddev);
if (ret)
return ret;
goto out;
break;
case ACTION_RECOVER:
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
@@ -5144,7 +5120,8 @@ action_store(struct mddev *mddev, const char *page, size_t len)
clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
break;
default:
return -EINVAL;
ret = -EINVAL;
goto out;
}
}
@@ -5152,14 +5129,18 @@ action_store(struct mddev *mddev, const char *page, size_t len)
/* A write to sync_action is enough to justify
* canceling read-auto mode
*/
flush_work(&mddev->sync_work);
mddev->ro = MD_RDWR;
md_wakeup_thread(mddev->sync_thread);
}
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
sysfs_notify_dirent_safe(mddev->sysfs_action);
return len;
ret = len;
out:
mddev_unlock(mddev);
return ret;
}
static struct md_sysfs_entry md_scan_mode =
drivers/md/md.h
-2
View File
@@ -595,8 +595,6 @@ struct mddev {
*/
struct list_head deleting;
/* Used to synchronize idle and frozen for action_store() */
struct mutex sync_mutex;
/* The sequence number for sync thread */
atomic_t sync_seq;