In mdadm commit 49b69533e8 ("mdmonitor: check if udev has finished
events processing") mdmonitor has been learnt to wait for udev to finish
processing, and later in commit 9935cf0f64f3 ("Mdmonitor: Improve udev
event handling") pooling for MD events on /proc/mdstat file has been
deprecated because relying on udev events is more reliable and less bug
prone (we are not competing with udev).
After those changes we are still observing missing mdmonitor events in
some scenarios, especially SpareEvent is likely to be missed. With this
patch MD will be able to generate more change uevents and wakeup
mdmonitor more frequently to give it possibility to notice events.
MD has md_new_events() functionality to trigger events and with this
patch this function is extended to generate udev CHANGE uevents. It
cannot be done directly because this function is called on interrupts
context, so appropriate workqueue is created. Uevents are less time
critical, it is safe to use workqueue. It is limited to CHANGE event as
there is no need to generate other uevents for now.
With this change, mdmonitor events are less likely to be missed. Our
internal tests suite confirms that, mdmonitor reliability is (again)
improved.
Signed-off-by: Mateusz Grzonka <mateusz.grzonka@xxxxxxxxx>
Signed-off-by: Kinga Stefaniuk <kinga.stefaniuk@xxxxxxxxx>
---
v8: fix possible conflict with del_work by adding spin_lock,
change default sync value to true, now false only on md_error
v7: add new work struct for these events, use md_misc_wq workqueue,
fix work cancellation
v6: use another workqueue and only on md_error, make configurable
if kobject_uevent is run immediately on event or queued
v5: fix flush_work missing and commit message fixes
v4: add more detailed commit message
v3: fix problems with calling function from interrupt context,
add work_queue and queue events notification
v2: resolve merge conflicts with applying the patch
Signed-off-by: Kinga Stefaniuk <kinga.stefaniuk@xxxxxxxxx>
---
drivers/md/md.c | 73 +++++++++++++++++++++++++++++++--------------
drivers/md/md.h | 3 +-
drivers/md/raid10.c | 2 +-
drivers/md/raid5.c | 2 +-
4 files changed, 55 insertions(+), 25 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 64693913ed18..d49031aba0d5 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -107,6 +107,7 @@ static int remove_and_add_spares(struct mddev *mddev,
static void mddev_detach(struct mddev *mddev);
static void export_rdev(struct md_rdev *rdev, struct mddev *mddev);
static void md_wakeup_thread_directly(struct md_thread __rcu *thread);
+static inline struct mddev *mddev_get(struct mddev *mddev);
/*
* Default number of read corrections we'll attempt on an rdev
@@ -323,6 +324,30 @@ static int start_readonly;
*/
static bool create_on_open = true;
+/*
+ * Enables to iterate over all existing md arrays
+ * all_mddevs_lock protects this list.
+ */
+static LIST_HEAD(all_mddevs);
+static DEFINE_SPINLOCK(all_mddevs_lock);
+
+/*
+ * Send every new event to the userspace.
+ */
+static void md_kobject_uevent_fn(struct work_struct *work)
+{
+ struct mddev *mddev = container_of(work, struct mddev, uevent_work);
+
+ spin_lock(&all_mddevs_lock);
+ mddev = mddev_get(mddev);
+ spin_unlock(&all_mddevs_lock);
+ if (!mddev)
+ return;
+
+ kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
+ mddev_put(mddev);
+}
+
/*
* We have a system wide 'event count' that is incremented
* on any 'interesting' event, and readers of /proc/mdstat
@@ -335,20 +360,21 @@ static bool create_on_open = true;
*/
static DECLARE_WAIT_QUEUE_HEAD(md_event_waiters);
static atomic_t md_event_count;
-void md_new_event(void)
+
+void md_new_event(struct mddev *mddev, bool sync)
{
atomic_inc(&md_event_count);
wake_up(&md_event_waiters);
+
+ if (mddev_is_dm(mddev))
+ return;
+ if (sync)
+ schedule_work(&mddev->uevent_work);
+ else
+ kobject_uevent(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE);
}
EXPORT_SYMBOL_GPL(md_new_event);
-/*
- * Enables to iterate over all existing md arrays
- * all_mddevs_lock protects this list.
- */
-static LIST_HEAD(all_mddevs);
-static DEFINE_SPINLOCK(all_mddevs_lock);
-
static bool is_md_suspended(struct mddev *mddev)
{
return percpu_ref_is_dying(&mddev->active_io);
@@ -773,6 +799,7 @@ int mddev_init(struct mddev *mddev)
mddev->resync_max = MaxSector;
mddev->level = LEVEL_NONE;
+ INIT_WORK(&mddev->uevent_work, md_kobject_uevent_fn);
INIT_WORK(&mddev->sync_work, md_start_sync);
INIT_WORK(&mddev->del_work, mddev_delayed_delete);
@@ -2898,7 +2925,7 @@ static int add_bound_rdev(struct md_rdev *rdev)
if (mddev->degraded)
set_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- md_new_event();
+ md_new_event(mddev, true);
return 0;
}
@@ -3015,7 +3042,7 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
md_kick_rdev_from_array(rdev);
if (mddev->pers)
set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
- md_new_event();
+ md_new_event(mddev, true);
}
}
} else if (cmd_match(buf, "writemostly")) {
@@ -4131,7 +4158,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
if (!mddev->thread)
md_update_sb(mddev, 1);
sysfs_notify_dirent_safe(mddev->sysfs_level);
- md_new_event();
+ md_new_event(mddev, true);
rv = len;
out_unlock:
mddev_unlock_and_resume(mddev);
@@ -4658,7 +4685,7 @@ new_dev_store(struct mddev *mddev, const char *buf, size_t len)
export_rdev(rdev, mddev);
mddev_unlock_and_resume(mddev);
if (!err)
- md_new_event();
+ md_new_event(mddev, true);
return err ? err : len;
}
@@ -5850,6 +5877,7 @@ static void mddev_delayed_delete(struct work_struct *ws)
{
struct mddev *mddev = container_of(ws, struct mddev, del_work);
+ cancel_work_sync(&mddev->uevent_work);
kobject_put(&mddev->kobj);
}
@@ -6276,7 +6304,7 @@ int md_run(struct mddev *mddev)
if (mddev->sb_flags)
md_update_sb(mddev, 0);
- md_new_event();
+ md_new_event(mddev, true);
return 0;
bitmap_abort:
@@ -6635,7 +6663,7 @@ static int do_md_stop(struct mddev *mddev, int mode)
if (mddev->hold_active == UNTIL_STOP)
mddev->hold_active = 0;
}
- md_new_event();
+ md_new_event(mddev, true);
sysfs_notify_dirent_safe(mddev->sysfs_state);
return 0;
}
@@ -7131,7 +7159,7 @@ static int hot_remove_disk(struct mddev *mddev, dev_t dev)
set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
if (!mddev->thread)
md_update_sb(mddev, 1);
- md_new_event();
+ md_new_event(mddev, true);
return 0;
busy:
@@ -7202,7 +7230,7 @@ static int hot_add_disk(struct mddev *mddev, dev_t dev)
* array immediately.
*/
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
- md_new_event();
+ md_new_event(mddev, true);
return 0;
abort_export:
@@ -8176,7 +8204,8 @@ void md_error(struct mddev *mddev, struct md_rdev *rdev)
}
if (mddev->event_work.func)
queue_work(md_misc_wq, &mddev->event_work);
- md_new_event();
+ if (!test_bit(MD_DELETED, &mddev->flags))
+ md_new_event(mddev, false);
}
EXPORT_SYMBOL(md_error);
@@ -9072,7 +9101,7 @@ void md_do_sync(struct md_thread *thread)
mddev->curr_resync = MD_RESYNC_ACTIVE; /* no longer delayed */
mddev->curr_resync_completed = j;
sysfs_notify_dirent_safe(mddev->sysfs_completed);
- md_new_event();
+ md_new_event(mddev, true);
update_time = jiffies;
blk_start_plug(&plug);
@@ -9144,7 +9173,7 @@ void md_do_sync(struct md_thread *thread)
/* this is the earliest that rebuild will be
* visible in /proc/mdstat
*/
- md_new_event();
+ md_new_event(mddev, true);
if (last_check + window > io_sectors || j == max_sectors)
continue;
@@ -9410,7 +9439,7 @@ static int remove_and_add_spares(struct mddev *mddev,
sysfs_link_rdev(mddev, rdev);
if (!test_bit(Journal, &rdev->flags))
spares++;
- md_new_event();
+ md_new_event(mddev, true);
set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
}
}
@@ -9529,7 +9558,7 @@ static void md_start_sync(struct work_struct *ws)
__mddev_resume(mddev, false);
md_wakeup_thread(mddev->sync_thread);
sysfs_notify_dirent_safe(mddev->sysfs_action);
- md_new_event();
+ md_new_event(mddev, true);
return;
not_running:
@@ -9781,7 +9810,7 @@ void md_reap_sync_thread(struct mddev *mddev)
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
sysfs_notify_dirent_safe(mddev->sysfs_completed);
sysfs_notify_dirent_safe(mddev->sysfs_action);
- md_new_event();
+ md_new_event(mddev, true);
if (mddev->event_work.func)
queue_work(md_misc_wq, &mddev->event_work);
wake_up(&resync_wait);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index a0d6827dced9..ab340618828c 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -582,6 +582,7 @@ struct mddev {
*/
struct work_struct flush_work;
struct work_struct event_work; /* used by dm to report failure event */
+ struct work_struct uevent_work;
mempool_t *serial_info_pool;
void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
struct md_cluster_info *cluster_info;
@@ -883,7 +884,7 @@ extern int md_super_wait(struct mddev *mddev);
extern int sync_page_io(struct md_rdev *rdev, sector_t sector, int size,
struct page *page, blk_opf_t opf, bool metadata_op);
extern void md_do_sync(struct md_thread *thread);
-extern void md_new_event(void);
+extern void md_new_event(struct mddev *mddev, bool sync);
extern void md_allow_write(struct mddev *mddev);
extern void md_wait_for_blocked_rdev(struct md_rdev *rdev, struct mddev *mddev);
extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 2a9c4ee982e0..f76571079845 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4542,7 +4542,7 @@ static int raid10_start_reshape(struct mddev *mddev)
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
conf->reshape_checkpoint = jiffies;
- md_new_event();
+ md_new_event(mddev, true);
return 0;
abort:
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index c14cf2410365..9da091b000d7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -8525,7 +8525,7 @@ static int raid5_start_reshape(struct mddev *mddev)
set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
conf->reshape_checkpoint = jiffies;
- md_new_event();
+ md_new_event(mddev, true);
return 0;
}
--
2.43.0
