2 files changed, 71 insertions, 52 deletions

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 270ee3a..41542eb 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -61,6 +61,10 @@ struct r5l_log {
 	struct list_head io_end_ios;	/* io_units which have been completely
 					 * written to the log but not yet written
 					 * to the RAID */
+	struct list_head flushing_ios;	/* io_units which are waiting for log
+					 * cache flush */
+	struct list_head flushed_ios;	/* io_units which settle down in log disk */
+	struct bio flush_bio;
 	struct list_head stripe_end_ios;/* io_units which have been completely
 					 * written to the RAID but have not yet
 					 * been considered for updating super */
@@ -114,8 +118,7 @@ enum r5l_io_unit_state {
 	IO_UNIT_IO_START = 1,	/* io_unit bio start writing to log,
 				 * don't accepting new bio */
 	IO_UNIT_IO_END = 2,	/* io_unit bio finish writing to log */
-	IO_UNIT_STRIPE_START = 3, /* stripes of io_unit are flushing to raid */
-	IO_UNIT_STRIPE_END = 4,	/* stripes data finished writing to raid */
+	IO_UNIT_STRIPE_END = 3,	/* stripes data finished writing to raid */
 };
 
 static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
@@ -229,7 +232,7 @@ static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
 		struct r5l_io_unit *last;
 		sector_t reclaimable_space;
 
-		r5l_move_io_unit_list(&log->io_end_ios, &log->stripe_end_ios,
+		r5l_move_io_unit_list(&log->flushed_ios, &log->stripe_end_ios,
 				      IO_UNIT_STRIPE_END);
 
 		last = list_last_entry(&log->stripe_end_ios,
@@ -559,6 +562,28 @@ void r5l_stripe_write_finished(struct stripe_head *sh)
 		r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
 }
 
+static void r5l_log_flush_endio(struct bio *bio)
+{
+	struct r5l_log *log = container_of(bio, struct r5l_log,
+		flush_bio);
+	unsigned long flags;
+	struct r5l_io_unit *io;
+	struct stripe_head *sh;
+
+	spin_lock_irqsave(&log->io_list_lock, flags);
+	list_for_each_entry(io, &log->flushing_ios, log_sibling) {
+		while (!list_empty(&io->stripe_list)) {
+			sh = list_first_entry(&io->stripe_list,
+				struct stripe_head, log_list);
+			list_del_init(&sh->log_list);
+			set_bit(STRIPE_HANDLE, &sh->state);
+			raid5_release_stripe(sh);
+		}
+	}
+	list_splice_tail_init(&log->flushing_ios, &log->flushed_ios);
+	spin_unlock_irqrestore(&log->io_list_lock, flags);
+}
+
 /*
  * Starting dispatch IO to raid.
  * io_unit(meta) consists of a log. There is one situation we want to avoid. A
@@ -575,44 +600,31 @@ void r5l_stripe_write_finished(struct stripe_head *sh)
  */
 void r5l_flush_stripe_to_raid(struct r5l_log *log)
 {
-	struct r5l_io_unit *io;
-	struct stripe_head *sh;
-	bool run_stripe;
-
+	bool do_flush;
 	if (!log)
 		return;
-	spin_lock_irq(&log->io_list_lock);
-	run_stripe = !list_empty(&log->io_end_ios);
-	spin_unlock_irq(&log->io_list_lock);
-
-	if (!run_stripe)
-		return;
-
-	blkdev_issue_flush(log->rdev->bdev, GFP_NOIO, NULL);
 
 	spin_lock_irq(&log->io_list_lock);
-	list_for_each_entry(io, &log->io_end_ios, log_sibling) {
-		if (io->state >= IO_UNIT_STRIPE_START)
-			continue;
-		__r5l_set_io_unit_state(io, IO_UNIT_STRIPE_START);
-
-		while (!list_empty(&io->stripe_list)) {
-			sh = list_first_entry(&io->stripe_list,
-					      struct stripe_head, log_list);
-			list_del_init(&sh->log_list);
-			set_bit(STRIPE_HANDLE, &sh->state);
-			raid5_release_stripe(sh);
-		}
+	/* flush bio is running */
+	if (!list_empty(&log->flushing_ios)) {
+		spin_unlock_irq(&log->io_list_lock);
+		return;
 	}
+	list_splice_tail_init(&log->io_end_ios, &log->flushing_ios);
+	do_flush = !list_empty(&log->flushing_ios);
 	spin_unlock_irq(&log->io_list_lock);
+
+	if (!do_flush)
+		return;
+	bio_reset(&log->flush_bio);
+	log->flush_bio.bi_bdev = log->rdev->bdev;
+	log->flush_bio.bi_end_io = r5l_log_flush_endio;
+	submit_bio(WRITE_FLUSH, &log->flush_bio);
 }
 
 static void r5l_kick_io_unit(struct r5l_log *log, struct r5l_io_unit *io)
 {
-	/* the log thread will write the io unit */
-	wait_event(io->wait_state, io->state >= IO_UNIT_IO_END);
-	if (io->state < IO_UNIT_STRIPE_START)
-		r5l_flush_stripe_to_raid(log);
+	md_wakeup_thread(log->rdev->mddev->thread);
 	wait_event(io->wait_state, io->state >= IO_UNIT_STRIPE_END);
 }
 
@@ -631,6 +643,8 @@ static void r5l_do_reclaim(struct r5l_log *log)
 	 * shouldn't reuse space of an unreclaimable io_unit
 	 */
 	while (1) {
+		struct list_head *target_list = NULL;
+
 		while (!list_empty(&log->stripe_end_ios)) {
 			io = list_first_entry(&log->stripe_end_ios,
 					      struct r5l_io_unit, log_sibling);
@@ -642,29 +656,26 @@ static void r5l_do_reclaim(struct r5l_log *log)
 		if (free >= reclaim_target ||
 		    (list_empty(&log->running_ios) &&
 		     list_empty(&log->io_end_ios) &&
-		     list_empty(&log->stripe_end_ios)))
+		     list_empty(&log->flushing_ios) &&
+		     list_empty(&log->flushed_ios)))
 			break;
 
 		/* Below waiting mostly happens when we shutdown the raid */
-		if (!list_empty(&log->io_end_ios)) {
-			io = list_first_entry(&log->io_end_ios,
-					      struct r5l_io_unit, log_sibling);
-			spin_unlock_irq(&log->io_list_lock);
-			/* nobody else can delete the io, we are safe */
-			r5l_kick_io_unit(log, io);
-			spin_lock_irq(&log->io_list_lock);
-			continue;
-		}
-
-		if (!list_empty(&log->running_ios)) {
-			io = list_first_entry(&log->running_ios,
-					      struct r5l_io_unit, log_sibling);
-			spin_unlock_irq(&log->io_list_lock);
-			/* nobody else can delete the io, we are safe */
-			r5l_kick_io_unit(log, io);
-			spin_lock_irq(&log->io_list_lock);
-			continue;
-		}
+		if (!list_empty(&log->flushed_ios))
+			target_list = &log->flushed_ios;
+		else if (!list_empty(&log->flushing_ios))
+			target_list = &log->flushing_ios;
+		else if (!list_empty(&log->io_end_ios))
+			target_list = &log->io_end_ios;
+		else if (!list_empty(&log->running_ios))
+			target_list = &log->running_ios;
+
+		io = list_first_entry(target_list,
+				      struct r5l_io_unit, log_sibling);
+		spin_unlock_irq(&log->io_list_lock);
+		/* nobody else can delete the io, we are safe */
+		r5l_kick_io_unit(log, io);
+		spin_lock_irq(&log->io_list_lock);
 	}
 	spin_unlock_irq(&log->io_list_lock);
 
@@ -1056,6 +1067,9 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 	INIT_LIST_HEAD(&log->running_ios);
 	INIT_LIST_HEAD(&log->io_end_ios);
 	INIT_LIST_HEAD(&log->stripe_end_ios);
+	INIT_LIST_HEAD(&log->flushing_ios);
+	INIT_LIST_HEAD(&log->flushed_ios);
+	bio_init(&log->flush_bio);
 
 	log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
 	if (!log->io_kc)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b0bf81d..46042c7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5740,8 +5740,12 @@ static int handle_active_stripes(struct r5conf *conf, int group,
 		for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
 			if (!list_empty(temp_inactive_list + i))
 				break;
-		if (i == NR_STRIPE_HASH_LOCKS)
+		if (i == NR_STRIPE_HASH_LOCKS) {
+			spin_unlock_irq(&conf->device_lock);
+			r5l_flush_stripe_to_raid(conf->log);
+			spin_lock_irq(&conf->device_lock);
 			return batch_size;
+		}
 		release_inactive = true;
 	}
 	spin_unlock_irq(&conf->device_lock);
@@ -5749,6 +5753,7 @@ static int handle_active_stripes(struct r5conf *conf, int group,
 	release_inactive_stripe_list(conf, temp_inactive_list,
 				     NR_STRIPE_HASH_LOCKS);
 
+	r5l_flush_stripe_to_raid(conf->log);
 	if (release_inactive) {
 		spin_lock_irq(&conf->device_lock);
 		return 0;