1 files changed, 303 insertions, 132 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9daa78c5fe33..4e033c26fdd4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -111,32 +111,48 @@ static void md_wakeup_thread_directly(struct md_thread __rcu *thread);
 /* Default safemode delay: 200 msec */
 #define DEFAULT_SAFEMODE_DELAY ((200 * HZ)/1000 +1)
 /*
- * Current RAID-1,4,5 parallel reconstruction 'guaranteed speed limit'
- * is 1000 KB/sec, so the extra system load does not show up that much.
- * Increase it if you want to have more _guaranteed_ speed. Note that
- * the RAID driver will use the maximum available bandwidth if the IO
- * subsystem is idle. There is also an 'absolute maximum' reconstruction
- * speed limit - in case reconstruction slows down your system despite
- * idle IO detection.
+ * Current RAID-1,4,5,6,10 parallel reconstruction 'guaranteed speed limit'
+ * is sysctl_speed_limit_min, 1000 KB/sec by default, so the extra system load
+ * does not show up that much. Increase it if you want to have more guaranteed
+ * speed. Note that the RAID driver will use the maximum bandwidth
+ * sysctl_speed_limit_max, 200 MB/sec by default, if the IO subsystem is idle.
  *
- * you can change it via /proc/sys/dev/raid/speed_limit_min and _max.
- * or /sys/block/mdX/md/sync_speed_{min,max}
+ * Background sync IO speed control:
+ *
+ * - below speed min:
+ *   no limit;
+ * - above speed min and below speed max:
+ *   a) if mddev is idle, then no limit;
+ *   b) if mddev is busy handling normal IO, then limit inflight sync IO
+ *   to sync_io_depth;
+ * - above speed max:
+ *   sync IO can't be issued;
+ *
+ * Following configurations can be changed via /proc/sys/dev/raid/ for system
+ * or /sys/block/mdX/md/ for one array.
  */
-
 static int sysctl_speed_limit_min = 1000;
 static int sysctl_speed_limit_max = 200000;
-static inline int speed_min(struct mddev *mddev)
+static int sysctl_sync_io_depth = 32;
+
+static int speed_min(struct mddev *mddev)
 {
 	return mddev->sync_speed_min ?
 		mddev->sync_speed_min : sysctl_speed_limit_min;
 }
 
-static inline int speed_max(struct mddev *mddev)
+static int speed_max(struct mddev *mddev)
 {
 	return mddev->sync_speed_max ?
 		mddev->sync_speed_max : sysctl_speed_limit_max;
 }
 
+static int sync_io_depth(struct mddev *mddev)
+{
+	return mddev->sync_io_depth ?
+		mddev->sync_io_depth : sysctl_sync_io_depth;
+}
+
 static void rdev_uninit_serial(struct md_rdev *rdev)
 {
 	if (!test_and_clear_bit(CollisionCheck, &rdev->flags))
@@ -293,14 +309,21 @@ static const struct ctl_table raid_table[] = {
 		.procname	= "speed_limit_min",
 		.data		= &sysctl_speed_limit_min,
 		.maxlen		= sizeof(int),
-		.mode		= S_IRUGO|S_IWUSR,
+		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
 	{
 		.procname	= "speed_limit_max",
 		.data		= &sysctl_speed_limit_max,
 		.maxlen		= sizeof(int),
-		.mode		= S_IRUGO|S_IWUSR,
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "sync_io_depth",
+		.data		= &sysctl_sync_io_depth,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
 };
@@ -316,6 +339,7 @@ static int start_readonly;
  * so all the races disappear.
  */
 static bool create_on_open = true;
+static bool legacy_async_del_gendisk = true;
 
 /*
  * We have a system wide 'event count' that is incremented
@@ -613,9 +637,12 @@ static void __mddev_put(struct mddev *mddev)
 	    mddev->ctime || mddev->hold_active)
 		return;
 
-	/* Array is not configured at all, and not held active, so destroy it */
+	/*
+	 * If array is freed by stopping array, MD_DELETED is set by
+	 * do_md_stop(), MD_DELETED is still set here in case mddev is freed
+	 * directly by closing a mddev that is created by create_on_open.
+	 */
 	set_bit(MD_DELETED, &mddev->flags);
-
 	/*
 	 * Call queue_work inside the spinlock so that flush_workqueue() after
 	 * mddev_find will succeed in waiting for the work to be done.
@@ -850,6 +877,19 @@ void mddev_unlock(struct mddev *mddev)
 		kobject_del(&rdev->kobj);
 		export_rdev(rdev, mddev);
 	}
+
+	if (!legacy_async_del_gendisk) {
+		/*
+		 * Call del_gendisk after release reconfig_mutex to avoid
+		 * deadlock (e.g. call del_gendisk under the lock and an
+		 * access to sysfs files waits the lock)
+		 * And MD_DELETED is only used for md raid which is set in
+		 * do_md_stop. dm raid only uses md_stop to stop. So dm raid
+		 * doesn't need to check MD_DELETED when getting reconfig lock
+		 */
+		if (test_bit(MD_DELETED, &mddev->flags))
+			del_gendisk(mddev->gendisk);
+	}
 }
 EXPORT_SYMBOL_GPL(mddev_unlock);
 
@@ -1379,13 +1419,13 @@ static int super_90_validate(struct mddev *mddev, struct md_rdev *freshest, stru
 			mddev->layout = -1;
 
 		if (sb->state & (1<<MD_SB_CLEAN))
-			mddev->recovery_cp = MaxSector;
+			mddev->resync_offset = MaxSector;
 		else {
 			if (sb->events_hi == sb->cp_events_hi &&
 				sb->events_lo == sb->cp_events_lo) {
-				mddev->recovery_cp = sb->recovery_cp;
+				mddev->resync_offset = sb->recovery_cp;
 			} else
-				mddev->recovery_cp = 0;
+				mddev->resync_offset = 0;
 		}
 
 		memcpy(mddev->uuid+0, &sb->set_uuid0, 4);
@@ -1511,10 +1551,10 @@ static void super_90_sync(struct mddev *mddev, struct md_rdev *rdev)
 	mddev->minor_version = sb->minor_version;
 	if (mddev->in_sync)
 	{
-		sb->recovery_cp = mddev->recovery_cp;
+		sb->recovery_cp = mddev->resync_offset;
 		sb->cp_events_hi = (mddev->events>>32);
 		sb->cp_events_lo = (u32)mddev->events;
-		if (mddev->recovery_cp == MaxSector)
+		if (mddev->resync_offset == MaxSector)
 			sb->state = (1<< MD_SB_CLEAN);
 	} else
 		sb->recovery_cp = 0;
@@ -1865,7 +1905,7 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *freshest, struc
 		mddev->bitmap_info.default_space = (4096-1024) >> 9;
 		mddev->reshape_backwards = 0;
 
-		mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
+		mddev->resync_offset = le64_to_cpu(sb->resync_offset);
 		memcpy(mddev->uuid, sb->set_uuid, 16);
 
 		mddev->max_disks =  (4096-256)/2;
@@ -2051,7 +2091,7 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
 	sb->utime = cpu_to_le64((__u64)mddev->utime);
 	sb->events = cpu_to_le64(mddev->events);
 	if (mddev->in_sync)
-		sb->resync_offset = cpu_to_le64(mddev->recovery_cp);
+		sb->resync_offset = cpu_to_le64(mddev->resync_offset);
 	else if (test_bit(MD_JOURNAL_CLEAN, &mddev->flags))
 		sb->resync_offset = cpu_to_le64(MaxSector);
 	else
@@ -2731,7 +2771,7 @@ repeat:
 	/* If this is just a dirty<->clean transition, and the array is clean
 	 * and 'events' is odd, we can roll back to the previous clean state */
 	if (nospares
-	    && (mddev->in_sync && mddev->recovery_cp == MaxSector)
+	    && (mddev->in_sync && mddev->resync_offset == MaxSector)
 	    && mddev->can_decrease_events
 	    && mddev->events != 1) {
 		mddev->events--;
@@ -4267,9 +4307,9 @@ __ATTR(chunk_size, S_IRUGO|S_IWUSR, chunk_size_show, chunk_size_store);
 static ssize_t
 resync_start_show(struct mddev *mddev, char *page)
 {
-	if (mddev->recovery_cp == MaxSector)
+	if (mddev->resync_offset == MaxSector)
 		return sprintf(page, "none\n");
-	return sprintf(page, "%llu\n", (unsigned long long)mddev->recovery_cp);
+	return sprintf(page, "%llu\n", (unsigned long long)mddev->resync_offset);
 }
 
 static ssize_t
@@ -4295,7 +4335,7 @@ resync_start_store(struct mddev *mddev, const char *buf, size_t len)
 		err = -EBUSY;
 
 	if (!err) {
-		mddev->recovery_cp = n;
+		mddev->resync_offset = n;
 		if (mddev->pers)
 			set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
 	}
@@ -4799,9 +4839,42 @@ out_unlock:
 static struct md_sysfs_entry md_metadata =
 __ATTR_PREALLOC(metadata_version, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
 
+static bool rdev_needs_recovery(struct md_rdev *rdev, sector_t sectors)
+{
+	return rdev->raid_disk >= 0 &&
+	       !test_bit(Journal, &rdev->flags) &&
+	       !test_bit(Faulty, &rdev->flags) &&
+	       !test_bit(In_sync, &rdev->flags) &&
+	       rdev->recovery_offset < sectors;
+}
+
+static enum sync_action md_get_active_sync_action(struct mddev *mddev)
+{
+	struct md_rdev *rdev;
+	bool is_recover = false;
+
+	if (mddev->resync_offset < MaxSector)
+		return ACTION_RESYNC;
+
+	if (mddev->reshape_position != MaxSector)
+		return ACTION_RESHAPE;
+
+	rcu_read_lock();
+	rdev_for_each_rcu(rdev, mddev) {
+		if (rdev_needs_recovery(rdev, MaxSector)) {
+			is_recover = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return is_recover ? ACTION_RECOVER : ACTION_IDLE;
+}
+
 enum sync_action md_sync_action(struct mddev *mddev)
 {
 	unsigned long recovery = mddev->recovery;
+	enum sync_action active_action;
 
 	/*
 	 * frozen has the highest priority, means running sync_thread will be
@@ -4825,8 +4898,17 @@ enum sync_action md_sync_action(struct mddev *mddev)
 	    !test_bit(MD_RECOVERY_NEEDED, &recovery))
 		return ACTION_IDLE;
 
-	if (test_bit(MD_RECOVERY_RESHAPE, &recovery) ||
-	    mddev->reshape_position != MaxSector)
+	/*
+	 * Check if any sync operation (resync/recover/reshape) is
+	 * currently active. This ensures that only one sync operation
+	 * can run at a time. Returns the type of active operation, or
+	 * ACTION_IDLE if none are active.
+	 */
+	active_action = md_get_active_sync_action(mddev);
+	if (active_action != ACTION_IDLE)
+		return active_action;
+
+	if (test_bit(MD_RECOVERY_RESHAPE, &recovery))
 		return ACTION_RESHAPE;
 
 	if (test_bit(MD_RECOVERY_RECOVER, &recovery))
@@ -5091,7 +5173,7 @@ static ssize_t
 sync_min_show(struct mddev *mddev, char *page)
 {
 	return sprintf(page, "%d (%s)\n", speed_min(mddev),
-		       mddev->sync_speed_min ? "local": "system");
+		       mddev->sync_speed_min ? "local" : "system");
 }
 
 static ssize_t
@@ -5100,7 +5182,7 @@ sync_min_store(struct mddev *mddev, const char *buf, size_t len)
 	unsigned int min;
 	int rv;
 
-	if (strncmp(buf, "system", 6)==0) {
+	if (strncmp(buf, "system", 6) == 0) {
 		min = 0;
 	} else {
 		rv = kstrtouint(buf, 10, &min);
@@ -5120,7 +5202,7 @@ static ssize_t
 sync_max_show(struct mddev *mddev, char *page)
 {
 	return sprintf(page, "%d (%s)\n", speed_max(mddev),
-		       mddev->sync_speed_max ? "local": "system");
+		       mddev->sync_speed_max ? "local" : "system");
 }
 
 static ssize_t
@@ -5129,7 +5211,7 @@ sync_max_store(struct mddev *mddev, const char *buf, size_t len)
 	unsigned int max;
 	int rv;
 
-	if (strncmp(buf, "system", 6)==0) {
+	if (strncmp(buf, "system", 6) == 0) {
 		max = 0;
 	} else {
 		rv = kstrtouint(buf, 10, &max);
@@ -5146,6 +5228,35 @@ static struct md_sysfs_entry md_sync_max =
 __ATTR(sync_speed_max, S_IRUGO|S_IWUSR, sync_max_show, sync_max_store);
 
 static ssize_t
+sync_io_depth_show(struct mddev *mddev, char *page)
+{
+	return sprintf(page, "%d (%s)\n", sync_io_depth(mddev),
+		       mddev->sync_io_depth ? "local" : "system");
+}
+
+static ssize_t
+sync_io_depth_store(struct mddev *mddev, const char *buf, size_t len)
+{
+	unsigned int max;
+	int rv;
+
+	if (strncmp(buf, "system", 6) == 0) {
+		max = 0;
+	} else {
+		rv = kstrtouint(buf, 10, &max);
+		if (rv < 0)
+			return rv;
+		if (max == 0)
+			return -EINVAL;
+	}
+	mddev->sync_io_depth = max;
+	return len;
+}
+
+static struct md_sysfs_entry md_sync_io_depth =
+__ATTR_RW(sync_io_depth);
+
+static ssize_t
 degraded_show(struct mddev *mddev, char *page)
 {
 	return sprintf(page, "%d\n", mddev->degraded);
@@ -5671,6 +5782,7 @@ static struct attribute *md_redundancy_attrs[] = {
 	&md_mismatches.attr,
 	&md_sync_min.attr,
 	&md_sync_max.attr,
+	&md_sync_io_depth.attr,
 	&md_sync_speed.attr,
 	&md_sync_force_parallel.attr,
 	&md_sync_completed.attr,
@@ -5721,19 +5833,30 @@ md_attr_store(struct kobject *kobj, struct attribute *attr,
 	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);
 	struct mddev *mddev = container_of(kobj, struct mddev, kobj);
 	ssize_t rv;
+	struct kernfs_node *kn = NULL;
 
 	if (!entry->store)
 		return -EIO;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
+
+	if (entry->store == array_state_store && cmd_match(page, "clear"))
+		kn = sysfs_break_active_protection(kobj, attr);
+
 	spin_lock(&all_mddevs_lock);
 	if (!mddev_get(mddev)) {
 		spin_unlock(&all_mddevs_lock);
+		if (kn)
+			sysfs_unbreak_active_protection(kn);
 		return -EBUSY;
 	}
 	spin_unlock(&all_mddevs_lock);
 	rv = entry->store(mddev, page, length);
 	mddev_put(mddev);
+
+	if (kn)
+		sysfs_unbreak_active_protection(kn);
+
 	return rv;
 }
 
@@ -5741,12 +5864,13 @@ static void md_kobj_release(struct kobject *ko)
 {
 	struct mddev *mddev = container_of(ko, struct mddev, kobj);
 
-	if (mddev->sysfs_state)
-		sysfs_put(mddev->sysfs_state);
-	if (mddev->sysfs_level)
-		sysfs_put(mddev->sysfs_level);
-
-	del_gendisk(mddev->gendisk);
+	if (legacy_async_del_gendisk) {
+		if (mddev->sysfs_state)
+			sysfs_put(mddev->sysfs_state);
+		if (mddev->sysfs_level)
+			sysfs_put(mddev->sysfs_level);
+		del_gendisk(mddev->gendisk);
+	}
 	put_disk(mddev->gendisk);
 }
 
@@ -5950,6 +6074,9 @@ static int md_alloc_and_put(dev_t dev, char *name)
 {
 	struct mddev *mddev = md_alloc(dev, name);
 
+	if (legacy_async_del_gendisk)
+		pr_warn("md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+\n");
+
 	if (IS_ERR(mddev))
 		return PTR_ERR(mddev);
 	mddev_put(mddev);
@@ -5995,7 +6122,7 @@ static int add_named_array(const char *val, const struct kernel_param *kp)
 
 static void md_safemode_timeout(struct timer_list *t)
 {
-	struct mddev *mddev = from_timer(mddev, t, safemode_timer);
+	struct mddev *mddev = timer_container_of(mddev, t, safemode_timer);
 
 	mddev->safemode = 1;
 	if (mddev->external)
@@ -6172,7 +6299,7 @@ int md_run(struct mddev *mddev)
 	}
 	if (err == 0 && pers->sync_request &&
 	    (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
-		err = mddev->bitmap_ops->create(mddev, -1);
+		err = mddev->bitmap_ops->create(mddev);
 		if (err)
 			pr_warn("%s: failed to create bitmap (%d)\n",
 				mdname(mddev), err);
@@ -6352,7 +6479,7 @@ static void md_clean(struct mddev *mddev)
 	mddev->external_size = 0;
 	mddev->dev_sectors = 0;
 	mddev->raid_disks = 0;
-	mddev->recovery_cp = 0;
+	mddev->resync_offset = 0;
 	mddev->resync_min = 0;
 	mddev->resync_max = MaxSector;
 	mddev->reshape_position = MaxSector;
@@ -6360,15 +6487,22 @@ static void md_clean(struct mddev *mddev)
 	mddev->persistent = 0;
 	mddev->level = LEVEL_NONE;
 	mddev->clevel[0] = 0;
+
 	/*
-	 * Don't clear MD_CLOSING, or mddev can be opened again.
-	 * 'hold_active != 0' means mddev is still in the creation
-	 * process and will be used later.
+	 * For legacy_async_del_gendisk mode, it can stop the array in the
+	 * middle of assembling it, then it still can access the array. So
+	 * it needs to clear MD_CLOSING. If not legacy_async_del_gendisk,
+	 * it can't open the array again after stopping it. So it doesn't
+	 * clear MD_CLOSING.
 	 */
-	if (mddev->hold_active)
-		mddev->flags = 0;
-	else
+	if (legacy_async_del_gendisk && mddev->hold_active) {
+		clear_bit(MD_CLOSING, &mddev->flags);
+	} else {
+		/* if UNTIL_STOP is set, it's cleared here */
+		mddev->hold_active = 0;
+		/* Don't clear MD_CLOSING, or mddev can be opened again. */
 		mddev->flags &= BIT_ULL_MASK(MD_CLOSING);
+	}
 	mddev->sb_flags = 0;
 	mddev->ro = MD_RDWR;
 	mddev->metadata_type[0] = 0;
@@ -6463,8 +6597,6 @@ static void __md_stop(struct mddev *mddev)
 	if (mddev->private)
 		pers->free(mddev, mddev->private);
 	mddev->private = NULL;
-	if (pers->sync_request && mddev->to_remove == NULL)
-		mddev->to_remove = &md_redundancy_group;
 	put_pers(pers);
 	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
 
@@ -6593,10 +6725,9 @@ static int do_md_stop(struct mddev *mddev, int mode)
 		mddev->bitmap_info.offset = 0;
 
 		export_array(mddev);
-
 		md_clean(mddev);
-		if (mddev->hold_active == UNTIL_STOP)
-			mddev->hold_active = 0;
+		if (!legacy_async_del_gendisk)
+			set_bit(MD_DELETED, &mddev->flags);
 	}
 	md_new_event();
 	sysfs_notify_dirent_safe(mddev->sysfs_state);
@@ -7232,7 +7363,7 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 	err = 0;
 	if (mddev->pers) {
 		if (fd >= 0) {
-			err = mddev->bitmap_ops->create(mddev, -1);
+			err = mddev->bitmap_ops->create(mddev);
 			if (!err)
 				err = mddev->bitmap_ops->load(mddev);
 
@@ -7306,9 +7437,9 @@ int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info)
 	 * openned
 	 */
 	if (info->state & (1<<MD_SB_CLEAN))
-		mddev->recovery_cp = MaxSector;
+		mddev->resync_offset = MaxSector;
 	else
-		mddev->recovery_cp = 0;
+		mddev->resync_offset = 0;
 	mddev->persistent    = ! info->not_persistent;
 	mddev->external	     = 0;
 
@@ -7548,7 +7679,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				mddev->bitmap_info.default_offset;
 			mddev->bitmap_info.space =
 				mddev->bitmap_info.default_space;
-			rv = mddev->bitmap_ops->create(mddev, -1);
+			rv = mddev->bitmap_ops->create(mddev);
 			if (!rv)
 				rv = mddev->bitmap_ops->load(mddev);
 
@@ -8247,7 +8378,7 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev)
 				seq_printf(seq, "\tresync=REMOTE");
 			return 1;
 		}
-		if (mddev->recovery_cp < MaxSector) {
+		if (mddev->resync_offset < MaxSector) {
 			seq_printf(seq, "\tresync=PENDING");
 			return 1;
 		}
@@ -8572,50 +8703,55 @@ void md_cluster_stop(struct mddev *mddev)
 	put_cluster_ops(mddev);
 }
 
-static int is_mddev_idle(struct mddev *mddev, int init)
+static bool is_rdev_holder_idle(struct md_rdev *rdev, bool init)
 {
+	unsigned long last_events = rdev->last_events;
+
+	if (!bdev_is_partition(rdev->bdev))
+		return true;
+
+	/*
+	 * If rdev is partition, and user doesn't issue IO to the array, the
+	 * array is still not idle if user issues IO to other partitions.
+	 */
+	rdev->last_events = part_stat_read_accum(rdev->bdev->bd_disk->part0,
+						 sectors) -
+			    part_stat_read_accum(rdev->bdev, sectors);
+
+	return init || rdev->last_events <= last_events;
+}
+
+/*
+ * mddev is idle if following conditions are matched since last check:
+ * 1) mddev doesn't have normal IO completed;
+ * 2) mddev doesn't have inflight normal IO;
+ * 3) if any member disk is partition, and other partitions don't have IO
+ *    completed;
+ *
+ * Noted this checking rely on IO accounting is enabled.
+ */
+static bool is_mddev_idle(struct mddev *mddev, int init)
+{
+	unsigned long last_events = mddev->normal_io_events;
+	struct gendisk *disk;
 	struct md_rdev *rdev;
-	int idle;
-	int curr_events;
+	bool idle = true;
 
-	idle = 1;
-	rcu_read_lock();
-	rdev_for_each_rcu(rdev, mddev) {
-		struct gendisk *disk = rdev->bdev->bd_disk;
+	disk = mddev_is_dm(mddev) ? mddev->dm_gendisk : mddev->gendisk;
+	if (!disk)
+		return true;
 
-		if (!init && !blk_queue_io_stat(disk->queue))
-			continue;
+	mddev->normal_io_events = part_stat_read_accum(disk->part0, sectors);
+	if (!init && (mddev->normal_io_events > last_events ||
+		      bdev_count_inflight(disk->part0)))
+		idle = false;
 
-		curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
-			      atomic_read(&disk->sync_io);
-		/* sync IO will cause sync_io to increase before the disk_stats
-		 * as sync_io is counted when a request starts, and
-		 * disk_stats is counted when it completes.
-		 * So resync activity will cause curr_events to be smaller than
-		 * when there was no such activity.
-		 * non-sync IO will cause disk_stat to increase without
-		 * increasing sync_io so curr_events will (eventually)
-		 * be larger than it was before.  Once it becomes
-		 * substantially larger, the test below will cause
-		 * the array to appear non-idle, and resync will slow
-		 * down.
-		 * If there is a lot of outstanding resync activity when
-		 * we set last_event to curr_events, then all that activity
-		 * completing might cause the array to appear non-idle
-		 * and resync will be slowed down even though there might
-		 * not have been non-resync activity.  This will only
-		 * happen once though.  'last_events' will soon reflect
-		 * the state where there is little or no outstanding
-		 * resync requests, and further resync activity will
-		 * always make curr_events less than last_events.
-		 *
-		 */
-		if (init || curr_events - rdev->last_events > 64) {
-			rdev->last_events = curr_events;
-			idle = 0;
-		}
-	}
+	rcu_read_lock();
+	rdev_for_each_rcu(rdev, mddev)
+		if (!is_rdev_holder_idle(rdev, init))
+			idle = false;
 	rcu_read_unlock();
+
 	return idle;
 }
 
@@ -8741,14 +8877,14 @@ static void md_bitmap_start(struct mddev *mddev,
 		mddev->pers->bitmap_sector(mddev, &md_io_clone->offset,
 					   &md_io_clone->sectors);
 
-	mddev->bitmap_ops->startwrite(mddev, md_io_clone->offset,
-				      md_io_clone->sectors);
+	mddev->bitmap_ops->start_write(mddev, md_io_clone->offset,
+				       md_io_clone->sectors);
 }
 
 static void md_bitmap_end(struct mddev *mddev, struct md_io_clone *md_io_clone)
 {
-	mddev->bitmap_ops->endwrite(mddev, md_io_clone->offset,
-				    md_io_clone->sectors);
+	mddev->bitmap_ops->end_write(mddev, md_io_clone->offset,
+				     md_io_clone->sectors);
 }
 
 static void md_end_clone_io(struct bio *bio)
@@ -8885,7 +9021,7 @@ static sector_t md_sync_position(struct mddev *mddev, enum sync_action action)
 		return mddev->resync_min;
 	case ACTION_RESYNC:
 		if (!mddev->bitmap)
-			return mddev->recovery_cp;
+			return mddev->resync_offset;
 		return 0;
 	case ACTION_RESHAPE:
 		/*
@@ -8901,11 +9037,7 @@ static sector_t md_sync_position(struct mddev *mddev, enum sync_action action)
 		start = MaxSector;
 		rcu_read_lock();
 		rdev_for_each_rcu(rdev, mddev)
-			if (rdev->raid_disk >= 0 &&
-			    !test_bit(Journal, &rdev->flags) &&
-			    !test_bit(Faulty, &rdev->flags) &&
-			    !test_bit(In_sync, &rdev->flags) &&
-			    rdev->recovery_offset < start)
+			if (rdev_needs_recovery(rdev, start))
 				start = rdev->recovery_offset;
 		rcu_read_unlock();
 
@@ -8927,6 +9059,23 @@ static sector_t md_sync_position(struct mddev *mddev, enum sync_action action)
 	}
 }
 
+static bool sync_io_within_limit(struct mddev *mddev)
+{
+	int io_sectors;
+
+	/*
+	 * For raid456, sync IO is stripe(4k) per IO, for other levels, it's
+	 * RESYNC_PAGES(64k) per IO.
+	 */
+	if (mddev->level == 4 || mddev->level == 5 || mddev->level == 6)
+		io_sectors = 8;
+	else
+		io_sectors = 128;
+
+	return atomic_read(&mddev->recovery_active) <
+		io_sectors * sync_io_depth(mddev);
+}
+
 #define SYNC_MARKS	10
 #define	SYNC_MARK_STEP	(3*HZ)
 #define UPDATE_FREQUENCY (5*60*HZ)
@@ -8976,6 +9125,11 @@ void md_do_sync(struct md_thread *thread)
 	}
 
 	action = md_sync_action(mddev);
+	if (action == ACTION_FROZEN || action == ACTION_IDLE) {
+		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+		goto skip;
+	}
+
 	desc = md_sync_action_name(action);
 	mddev->last_sync_action = action;
 
@@ -9106,8 +9260,8 @@ void md_do_sync(struct md_thread *thread)
 				   atomic_read(&mddev->recovery_active) == 0);
 			mddev->curr_resync_completed = j;
 			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
-			    j > mddev->recovery_cp)
-				mddev->recovery_cp = j;
+			    j > mddev->resync_offset)
+				mddev->resync_offset = j;
 			update_time = jiffies;
 			set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
 			sysfs_notify_dirent_safe(mddev->sysfs_completed);
@@ -9195,7 +9349,8 @@ void md_do_sync(struct md_thread *thread)
 				msleep(500);
 				goto repeat;
 			}
-			if (!is_mddev_idle(mddev, 0)) {
+			if (!sync_io_within_limit(mddev) &&
+			    !is_mddev_idle(mddev, 0)) {
 				/*
 				 * Give other IO more of a chance.
 				 * The faster the devices, the less we wait.
@@ -9226,19 +9381,19 @@ void md_do_sync(struct md_thread *thread)
 	    mddev->curr_resync > MD_RESYNC_ACTIVE) {
 		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
 			if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
-				if (mddev->curr_resync >= mddev->recovery_cp) {
+				if (mddev->curr_resync >= mddev->resync_offset) {
 					pr_debug("md: checkpointing %s of %s.\n",
 						 desc, mdname(mddev));
 					if (test_bit(MD_RECOVERY_ERROR,
 						&mddev->recovery))
-						mddev->recovery_cp =
+						mddev->resync_offset =
 							mddev->curr_resync_completed;
 					else
-						mddev->recovery_cp =
+						mddev->resync_offset =
 							mddev->curr_resync;
 				}
 			} else
-				mddev->recovery_cp = MaxSector;
+				mddev->resync_offset = MaxSector;
 		} else {
 			if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 				mddev->curr_resync = MaxSector;
@@ -9246,12 +9401,8 @@ void md_do_sync(struct md_thread *thread)
 			    test_bit(MD_RECOVERY_RECOVER, &mddev->recovery)) {
 				rcu_read_lock();
 				rdev_for_each_rcu(rdev, mddev)
-					if (rdev->raid_disk >= 0 &&
-					    mddev->delta_disks >= 0 &&
-					    !test_bit(Journal, &rdev->flags) &&
-					    !test_bit(Faulty, &rdev->flags) &&
-					    !test_bit(In_sync, &rdev->flags) &&
-					    rdev->recovery_offset < mddev->curr_resync)
+					if (mddev->delta_disks >= 0 &&
+					    rdev_needs_recovery(rdev, mddev->curr_resync))
 						rdev->recovery_offset = mddev->curr_resync;
 				rcu_read_unlock();
 			}
@@ -9342,6 +9493,12 @@ static bool rdev_is_spare(struct md_rdev *rdev)
 
 static bool rdev_addable(struct md_rdev *rdev)
 {
+	struct mddev *mddev;
+
+	mddev = READ_ONCE(rdev->mddev);
+	if (!mddev)
+		return false;
+
 	/* rdev is already used, don't add it again. */
 	if (test_bit(Candidate, &rdev->flags) || rdev->raid_disk >= 0 ||
 	    test_bit(Faulty, &rdev->flags))
@@ -9352,7 +9509,7 @@ static bool rdev_addable(struct md_rdev *rdev)
 		return true;
 
 	/* Allow to add if array is read-write. */
-	if (md_is_rdwr(rdev->mddev))
+	if (md_is_rdwr(mddev))
 		return true;
 
 	/*
@@ -9380,17 +9537,11 @@ static bool md_spares_need_change(struct mddev *mddev)
 	return false;
 }
 
-static int remove_and_add_spares(struct mddev *mddev,
-				 struct md_rdev *this)
+static int remove_spares(struct mddev *mddev, struct md_rdev *this)
 {
 	struct md_rdev *rdev;
-	int spares = 0;
 	int removed = 0;
 
-	if (this && test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
-		/* Mustn't remove devices when resync thread is running */
-		return 0;
-
 	rdev_for_each(rdev, mddev) {
 		if ((this == NULL || rdev == this) && rdev_removeable(rdev) &&
 		    !mddev->pers->hot_remove_disk(mddev, rdev)) {
@@ -9404,6 +9555,21 @@ static int remove_and_add_spares(struct mddev *mddev,
 	if (removed && mddev->kobj.sd)
 		sysfs_notify_dirent_safe(mddev->sysfs_degraded);
 
+	return removed;
+}
+
+static int remove_and_add_spares(struct mddev *mddev,
+				 struct md_rdev *this)
+{
+	struct md_rdev *rdev;
+	int spares = 0;
+	int removed = 0;
+
+	if (this && test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
+		/* Mustn't remove devices when resync thread is running */
+		return 0;
+
+	removed = remove_spares(mddev, this);
 	if (this && removed)
 		goto no_add;
 
@@ -9445,7 +9611,8 @@ static bool md_choose_sync_action(struct mddev *mddev, int *spares)
 	}
 
 	/* Check if resync is in progress. */
-	if (mddev->recovery_cp < MaxSector) {
+	if (mddev->resync_offset < MaxSector) {
+		remove_spares(mddev, NULL);
 		set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 		clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery);
 		return true;
@@ -9625,7 +9792,7 @@ void md_check_recovery(struct mddev *mddev)
 		test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
 		(mddev->external == 0 && mddev->safemode == 1) ||
 		(mddev->safemode == 2
-		 && !mddev->in_sync && mddev->recovery_cp == MaxSector)
+		 && !mddev->in_sync && mddev->resync_offset == MaxSector)
 		))
 		return;
 
@@ -9682,8 +9849,8 @@ void md_check_recovery(struct mddev *mddev)
 			 * remove disk.
 			 */
 			rdev_for_each_safe(rdev, tmp, mddev) {
-				if (test_and_clear_bit(ClusterRemove, &rdev->flags) &&
-						rdev->raid_disk < 0)
+				if (rdev->raid_disk < 0 &&
+				    test_and_clear_bit(ClusterRemove, &rdev->flags))
 					md_kick_rdev_from_array(rdev);
 			}
 		}
@@ -9989,8 +10156,11 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
 
 	/* Check for change of roles in the active devices */
 	rdev_for_each_safe(rdev2, tmp, mddev) {
-		if (test_bit(Faulty, &rdev2->flags))
+		if (test_bit(Faulty, &rdev2->flags)) {
+			if (test_bit(ClusterRemove, &rdev2->flags))
+				set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 			continue;
+		}
 
 		/* Check if the roles changed */
 		role = le16_to_cpu(sb->dev_roles[rdev2->desc_nr]);
@@ -10288,6 +10458,7 @@ module_param_call(start_ro, set_ro, get_ro, NULL, S_IRUSR|S_IWUSR);
 module_param(start_dirty_degraded, int, S_IRUGO|S_IWUSR);
 module_param_call(new_array, add_named_array, NULL, NULL, S_IWUSR);
 module_param(create_on_open, bool, S_IRUSR|S_IWUSR);
+module_param(legacy_async_del_gendisk, bool, 0600);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("MD RAID framework");