3 files changed, 430 insertions, 41 deletions

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 19c5af91bd1b..7dec2a04ca26 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -29,12 +29,21 @@
 #define BLOCK_SECTORS (8)
 
 /*
- * reclaim runs every 1/4 disk size or 10G reclaimable space. This can prevent
- * recovery scans a very long log
+ * log->max_free_space is min(1/4 disk size, 10G reclaimable space).
+ *
+ * In write through mode, the reclaim runs every log->max_free_space.
+ * This can prevent the recovery scans for too long
  */
 #define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */
 #define RECLAIM_MAX_FREE_SPACE_SHIFT (2)
 
+/* wake up reclaim thread periodically */
+#define R5C_RECLAIM_WAKEUP_INTERVAL (30 * HZ)
+/* start flush with these full stripes */
+#define R5C_FULL_STRIPE_FLUSH_BATCH 256
+/* reclaim stripes in groups */
+#define R5C_RECLAIM_STRIPE_GROUP (NR_STRIPE_HASH_LOCKS * 2)
+
 /*
  * We only need 2 bios per I/O unit to make progress, but ensure we
  * have a few more available to not get too tight.
@@ -141,6 +150,12 @@ struct r5l_log {
 
 	/* for r5c_cache */
 	enum r5c_journal_mode r5c_journal_mode;
+
+	/* all stripes in r5cache, in the order of seq at sh->log_start */
+	struct list_head stripe_in_journal_list;
+
+	spinlock_t stripe_in_journal_lock;
+	atomic_t stripe_in_journal_count;
 };
 
 /*
@@ -256,11 +271,109 @@ void r5c_handle_cached_data_endio(struct r5conf *conf,
 	}
 }
 
+/* Check whether we should flush some stripes to free up stripe cache */
+void r5c_check_stripe_cache_usage(struct r5conf *conf)
+{
+	int total_cached;
+
+	if (!r5c_is_writeback(conf->log))
+		return;
+
+	total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
+		atomic_read(&conf->r5c_cached_full_stripes);
+
+	/*
+	 * The following condition is true for either of the following:
+	 *   - stripe cache pressure high:
+	 *          total_cached > 3/4 min_nr_stripes ||
+	 *          empty_inactive_list_nr > 0
+	 *   - stripe cache pressure moderate:
+	 *          total_cached > 1/2 min_nr_stripes
+	 */
+	if (total_cached > conf->min_nr_stripes * 1 / 2 ||
+	    atomic_read(&conf->empty_inactive_list_nr) > 0)
+		r5l_wake_reclaim(conf->log, 0);
+}
+
+/*
+ * flush cache when there are R5C_FULL_STRIPE_FLUSH_BATCH or more full
+ * stripes in the cache
+ */
+void r5c_check_cached_full_stripe(struct r5conf *conf)
+{
+	if (!r5c_is_writeback(conf->log))
+		return;
+
+	/*
+	 * wake up reclaim for R5C_FULL_STRIPE_FLUSH_BATCH cached stripes
+	 * or a full stripe (chunk size / 4k stripes).
+	 */
+	if (atomic_read(&conf->r5c_cached_full_stripes) >=
+	    min(R5C_FULL_STRIPE_FLUSH_BATCH,
+		conf->chunk_sectors >> STRIPE_SHIFT))
+		r5l_wake_reclaim(conf->log, 0);
+}
+
+/*
+ * Total log space (in sectors) needed to flush all data in cache
+ *
+ * Currently, writing-out phase automatically includes all pending writes
+ * to the same sector. So the reclaim of each stripe takes up to
+ * (conf->raid_disks + 1) pages of log space.
+ *
+ * To totally avoid deadlock due to log space, the code reserves
+ * (conf->raid_disks + 1) pages for each stripe in cache, which is not
+ * necessary in most cases.
+ *
+ * To improve this, we will need writing-out phase to be able to NOT include
+ * pending writes, which will reduce the requirement to
+ * (conf->max_degraded + 1) pages per stripe in cache.
+ */
+static sector_t r5c_log_required_to_flush_cache(struct r5conf *conf)
+{
+	struct r5l_log *log = conf->log;
+
+	if (!r5c_is_writeback(log))
+		return 0;
+
+	return BLOCK_SECTORS * (conf->raid_disks + 1) *
+		atomic_read(&log->stripe_in_journal_count);
+}
+
+/*
+ * evaluate log space usage and update R5C_LOG_TIGHT and R5C_LOG_CRITICAL
+ *
+ * R5C_LOG_TIGHT is set when free space on the log device is less than 3x of
+ * reclaim_required_space. R5C_LOG_CRITICAL is set when free space on the log
+ * device is less than 2x of reclaim_required_space.
+ */
+static inline void r5c_update_log_state(struct r5l_log *log)
+{
+	struct r5conf *conf = log->rdev->mddev->private;
+	sector_t free_space;
+	sector_t reclaim_space;
+
+	if (!r5c_is_writeback(log))
+		return;
+
+	free_space = r5l_ring_distance(log, log->log_start,
+				       log->last_checkpoint);
+	reclaim_space = r5c_log_required_to_flush_cache(conf);
+	if (free_space < 2 * reclaim_space)
+		set_bit(R5C_LOG_CRITICAL, &conf->cache_state);
+	else
+		clear_bit(R5C_LOG_CRITICAL, &conf->cache_state);
+	if (free_space < 3 * reclaim_space)
+		set_bit(R5C_LOG_TIGHT, &conf->cache_state);
+	else
+		clear_bit(R5C_LOG_TIGHT, &conf->cache_state);
+}
+
 /*
  * Put the stripe into writing-out phase by clearing STRIPE_R5C_CACHING.
  * This function should only be called in write-back mode.
  */
-static void r5c_make_stripe_write_out(struct stripe_head *sh)
+void r5c_make_stripe_write_out(struct stripe_head *sh)
 {
 	struct r5conf *conf = sh->raid_conf;
 	struct r5l_log *log = conf->log;
@@ -440,6 +553,7 @@ static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io)
 {
 	log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
 
+	r5c_update_log_state(log);
 	/*
 	 * If we filled up the log device start from the beginning again,
 	 * which will require a new bio.
@@ -600,21 +714,43 @@ static int r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
 	atomic_inc(&io->pending_stripe);
 	sh->log_io = io;
 
+	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+		return 0;
+
+	if (sh->log_start == MaxSector) {
+		BUG_ON(!list_empty(&sh->r5c));
+		sh->log_start = io->log_start;
+		spin_lock_irq(&log->stripe_in_journal_lock);
+		list_add_tail(&sh->r5c,
+			      &log->stripe_in_journal_list);
+		spin_unlock_irq(&log->stripe_in_journal_lock);
+		atomic_inc(&log->stripe_in_journal_count);
+	}
 	return 0;
 }
 
-static void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
+/* add stripe to no_space_stripes, and then wake up reclaim */
+static inline void r5l_add_no_space_stripe(struct r5l_log *log,
+					   struct stripe_head *sh)
+{
+	spin_lock(&log->no_space_stripes_lock);
+	list_add_tail(&sh->log_list, &log->no_space_stripes);
+	spin_unlock(&log->no_space_stripes_lock);
+}
+
 /*
  * running in raid5d, where reclaim could wait for raid5d too (when it flushes
  * data from log to raid disks), so we shouldn't wait for reclaim here
  */
 int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
 {
+	struct r5conf *conf = sh->raid_conf;
 	int write_disks = 0;
 	int data_pages, parity_pages;
 	int reserve;
 	int i;
 	int ret = 0;
+	bool wake_reclaim = false;
 
 	if (!log)
 		return -EAGAIN;
@@ -658,22 +794,49 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
 	mutex_lock(&log->io_mutex);
 	/* meta + data */
 	reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
-	if (!r5l_has_free_space(log, reserve)) {
-		spin_lock(&log->no_space_stripes_lock);
-		list_add_tail(&sh->log_list, &log->no_space_stripes);
-		spin_unlock(&log->no_space_stripes_lock);
 
-		r5l_wake_reclaim(log, reserve);
-	} else {
-		ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
-		if (ret) {
-			spin_lock_irq(&log->io_list_lock);
-			list_add_tail(&sh->log_list, &log->no_mem_stripes);
-			spin_unlock_irq(&log->io_list_lock);
+	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH) {
+		if (!r5l_has_free_space(log, reserve)) {
+			r5l_add_no_space_stripe(log, sh);
+			wake_reclaim = true;
+		} else {
+			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
+			if (ret) {
+				spin_lock_irq(&log->io_list_lock);
+				list_add_tail(&sh->log_list,
+					      &log->no_mem_stripes);
+				spin_unlock_irq(&log->io_list_lock);
+			}
+		}
+	} else {  /* R5C_JOURNAL_MODE_WRITE_BACK */
+		/*
+		 * log space critical, do not process stripes that are
+		 * not in cache yet (sh->log_start == MaxSector).
+		 */
+		if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
+		    sh->log_start == MaxSector) {
+			r5l_add_no_space_stripe(log, sh);
+			wake_reclaim = true;
+			reserve = 0;
+		} else if (!r5l_has_free_space(log, reserve)) {
+			if (sh->log_start == log->last_checkpoint)
+				BUG();
+			else
+				r5l_add_no_space_stripe(log, sh);
+		} else {
+			ret = r5l_log_stripe(log, sh, data_pages, parity_pages);
+			if (ret) {
+				spin_lock_irq(&log->io_list_lock);
+				list_add_tail(&sh->log_list,
+					      &log->no_mem_stripes);
+				spin_unlock_irq(&log->io_list_lock);
+			}
 		}
 	}
 
 	mutex_unlock(&log->io_mutex);
+	if (wake_reclaim)
+		r5l_wake_reclaim(log, reserve);
 	return 0;
 }
 
@@ -720,10 +883,40 @@ static void r5l_run_no_space_stripes(struct r5l_log *log)
 	spin_unlock(&log->no_space_stripes_lock);
 }
 
+/*
+ * calculate new last_checkpoint
+ * for write through mode, returns log->next_checkpoint
+ * for write back, returns log_start of first sh in stripe_in_journal_list
+ */
+static sector_t r5c_calculate_new_cp(struct r5conf *conf)
+{
+	struct stripe_head *sh;
+	struct r5l_log *log = conf->log;
+	sector_t new_cp;
+	unsigned long flags;
+
+	if (log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+		return log->next_checkpoint;
+
+	spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
+	if (list_empty(&conf->log->stripe_in_journal_list)) {
+		/* all stripes flushed */
+		spin_unlock(&log->stripe_in_journal_lock);
+		return log->next_checkpoint;
+	}
+	sh = list_first_entry(&conf->log->stripe_in_journal_list,
+			      struct stripe_head, r5c);
+	new_cp = sh->log_start;
+	spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
+	return new_cp;
+}
+
 static sector_t r5l_reclaimable_space(struct r5l_log *log)
 {
+	struct r5conf *conf = log->rdev->mddev->private;
+
 	return r5l_ring_distance(log, log->last_checkpoint,
-				 log->next_checkpoint);
+				 r5c_calculate_new_cp(conf));
 }
 
 static void r5l_run_no_mem_stripe(struct r5l_log *log)
@@ -769,6 +962,7 @@ static bool r5l_complete_finished_ios(struct r5l_log *log)
 static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
 {
 	struct r5l_log *log = io->log;
+	struct r5conf *conf = log->rdev->mddev->private;
 	unsigned long flags;
 
 	spin_lock_irqsave(&log->io_list_lock, flags);
@@ -779,7 +973,8 @@ static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
 		return;
 	}
 
-	if (r5l_reclaimable_space(log) > log->max_free_space)
+	if (r5l_reclaimable_space(log) > log->max_free_space ||
+	    test_bit(R5C_LOG_TIGHT, &conf->cache_state))
 		r5l_wake_reclaim(log, 0);
 
 	spin_unlock_irqrestore(&log->io_list_lock, flags);
@@ -900,14 +1095,146 @@ static void r5l_write_super_and_discard_space(struct r5l_log *log,
 	}
 }
 
+/*
+ * r5c_flush_stripe moves stripe from cached list to handle_list. When called,
+ * the stripe must be on r5c_cached_full_stripes or r5c_cached_partial_stripes.
+ *
+ * must hold conf->device_lock
+ */
+static void r5c_flush_stripe(struct r5conf *conf, struct stripe_head *sh)
+{
+	BUG_ON(list_empty(&sh->lru));
+	BUG_ON(!test_bit(STRIPE_R5C_CACHING, &sh->state));
+	BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
+
+	/*
+	 * The stripe is not ON_RELEASE_LIST, so it is safe to call
+	 * raid5_release_stripe() while holding conf->device_lock
+	 */
+	BUG_ON(test_bit(STRIPE_ON_RELEASE_LIST, &sh->state));
+	assert_spin_locked(&conf->device_lock);
+
+	list_del_init(&sh->lru);
+	atomic_inc(&sh->count);
+
+	set_bit(STRIPE_HANDLE, &sh->state);
+	atomic_inc(&conf->active_stripes);
+	r5c_make_stripe_write_out(sh);
+
+	if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+		atomic_inc(&conf->preread_active_stripes);
+	raid5_release_stripe(sh);
+}
+
+/*
+ * if num == 0, flush all full stripes
+ * if num > 0, flush all full stripes. If less than num full stripes are
+ *             flushed, flush some partial stripes until totally num stripes are
+ *             flushed or there is no more cached stripes.
+ */
+void r5c_flush_cache(struct r5conf *conf, int num)
+{
+	int count;
+	struct stripe_head *sh, *next;
+
+	assert_spin_locked(&conf->device_lock);
+	if (!conf->log)
+		return;
+
+	count = 0;
+	list_for_each_entry_safe(sh, next, &conf->r5c_full_stripe_list, lru) {
+		r5c_flush_stripe(conf, sh);
+		count++;
+	}
+
+	if (count >= num)
+		return;
+	list_for_each_entry_safe(sh, next,
+				 &conf->r5c_partial_stripe_list, lru) {
+		r5c_flush_stripe(conf, sh);
+		if (++count >= num)
+			break;
+	}
+}
+
+static void r5c_do_reclaim(struct r5conf *conf)
+{
+	struct r5l_log *log = conf->log;
+	struct stripe_head *sh;
+	int count = 0;
+	unsigned long flags;
+	int total_cached;
+	int stripes_to_flush;
+
+	if (!r5c_is_writeback(log))
+		return;
+
+	total_cached = atomic_read(&conf->r5c_cached_partial_stripes) +
+		atomic_read(&conf->r5c_cached_full_stripes);
+
+	if (total_cached > conf->min_nr_stripes * 3 / 4 ||
+	    atomic_read(&conf->empty_inactive_list_nr) > 0)
+		/*
+		 * if stripe cache pressure high, flush all full stripes and
+		 * some partial stripes
+		 */
+		stripes_to_flush = R5C_RECLAIM_STRIPE_GROUP;
+	else if (total_cached > conf->min_nr_stripes * 1 / 2 ||
+		 atomic_read(&conf->r5c_cached_full_stripes) >
+		 R5C_FULL_STRIPE_FLUSH_BATCH)
+		/*
+		 * if stripe cache pressure moderate, or if there is many full
+		 * stripes,flush all full stripes
+		 */
+		stripes_to_flush = 0;
+	else
+		/* no need to flush */
+		stripes_to_flush = -1;
+
+	if (stripes_to_flush >= 0) {
+		spin_lock_irqsave(&conf->device_lock, flags);
+		r5c_flush_cache(conf, stripes_to_flush);
+		spin_unlock_irqrestore(&conf->device_lock, flags);
+	}
+
+	/* if log space is tight, flush stripes on stripe_in_journal_list */
+	if (test_bit(R5C_LOG_TIGHT, &conf->cache_state)) {
+		spin_lock_irqsave(&log->stripe_in_journal_lock, flags);
+		spin_lock(&conf->device_lock);
+		list_for_each_entry(sh, &log->stripe_in_journal_list, r5c) {
+			/*
+			 * stripes on stripe_in_journal_list could be in any
+			 * state of the stripe_cache state machine. In this
+			 * case, we only want to flush stripe on
+			 * r5c_cached_full/partial_stripes. The following
+			 * condition makes sure the stripe is on one of the
+			 * two lists.
+			 */
+			if (!list_empty(&sh->lru) &&
+			    !test_bit(STRIPE_HANDLE, &sh->state) &&
+			    atomic_read(&sh->count) == 0) {
+				r5c_flush_stripe(conf, sh);
+			}
+			if (count++ >= R5C_RECLAIM_STRIPE_GROUP)
+				break;
+		}
+		spin_unlock(&conf->device_lock);
+		spin_unlock_irqrestore(&log->stripe_in_journal_lock, flags);
+	}
+	md_wakeup_thread(conf->mddev->thread);
+}
+
 static void r5l_do_reclaim(struct r5l_log *log)
 {
+	struct r5conf *conf = log->rdev->mddev->private;
 	sector_t reclaim_target = xchg(&log->reclaim_target, 0);
 	sector_t reclaimable;
 	sector_t next_checkpoint;
-	u64 next_cp_seq;
+	bool write_super;
 
 	spin_lock_irq(&log->io_list_lock);
+	write_super = r5l_reclaimable_space(log) > log->max_free_space ||
+		reclaim_target != 0 || !list_empty(&log->no_space_stripes);
 	/*
 	 * move proper io_unit to reclaim list. We should not change the order.
 	 * reclaimable/unreclaimable io_unit can be mixed in the list, we
@@ -928,12 +1255,12 @@ static void r5l_do_reclaim(struct r5l_log *log)
 				    log->io_list_lock);
 	}
 
-	next_checkpoint = log->next_checkpoint;
-	next_cp_seq = log->next_cp_seq;
+	next_checkpoint = r5c_calculate_new_cp(conf);
 	spin_unlock_irq(&log->io_list_lock);
 
 	BUG_ON(reclaimable < 0);
-	if (reclaimable == 0)
+
+	if (reclaimable == 0 || !write_super)
 		return;
 
 	/*
@@ -945,7 +1272,7 @@ static void r5l_do_reclaim(struct r5l_log *log)
 
 	mutex_lock(&log->io_mutex);
 	log->last_checkpoint = next_checkpoint;
-	log->last_cp_seq = next_cp_seq;
+	r5c_update_log_state(log);
 	mutex_unlock(&log->io_mutex);
 
 	r5l_run_no_space_stripes(log);
@@ -959,14 +1286,17 @@ static void r5l_reclaim_thread(struct md_thread *thread)
 
 	if (!log)
 		return;
+	r5c_do_reclaim(conf);
 	r5l_do_reclaim(log);
 }
 
-static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
+void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
 {
 	unsigned long target;
 	unsigned long new = (unsigned long)space; /* overflow in theory */
 
+	if (!log)
+		return;
 	do {
 		target = log->reclaim_target;
 		if (new < target)
@@ -990,11 +1320,12 @@ void r5l_quiesce(struct r5l_log *log, int state)
 			return;
 		log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
 					log->rdev->mddev, "reclaim");
+		log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
 	} else if (state == 1) {
 		/* make sure r5l_write_super_and_discard_space exits */
 		mddev = log->rdev->mddev;
 		wake_up(&mddev->sb_wait);
-		r5l_wake_reclaim(log, -1L);
+		r5l_wake_reclaim(log, MaxSector);
 		md_unregister_thread(&log->reclaim_thread);
 		r5l_do_reclaim(log);
 	}
@@ -1415,12 +1746,22 @@ void r5c_finish_stripe_write_out(struct r5conf *conf,
 
 	if (do_wakeup)
 		wake_up(&conf->wait_for_overlap);
+
+	if (conf->log->r5c_journal_mode == R5C_JOURNAL_MODE_WRITE_THROUGH)
+		return;
+
+	spin_lock_irq(&conf->log->stripe_in_journal_lock);
+	list_del_init(&sh->r5c);
+	spin_unlock_irq(&conf->log->stripe_in_journal_lock);
+	sh->log_start = MaxSector;
+	atomic_dec(&conf->log->stripe_in_journal_count);
 }
 
 int
 r5c_cache_data(struct r5l_log *log, struct stripe_head *sh,
 	       struct stripe_head_state *s)
 {
+	struct r5conf *conf = sh->raid_conf;
 	int pages = 0;
 	int reserve;
 	int i;
@@ -1451,12 +1792,15 @@ r5c_cache_data(struct r5l_log *log, struct stripe_head *sh,
 	mutex_lock(&log->io_mutex);
 	/* meta + data */
 	reserve = (1 + pages) << (PAGE_SHIFT - 9);
-	if (!r5l_has_free_space(log, reserve)) {
-		spin_lock(&log->no_space_stripes_lock);
-		list_add_tail(&sh->log_list, &log->no_space_stripes);
-		spin_unlock(&log->no_space_stripes_lock);
 
-		r5l_wake_reclaim(log, reserve);
+	if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
+	    sh->log_start == MaxSector)
+		r5l_add_no_space_stripe(log, sh);
+	else if (!r5l_has_free_space(log, reserve)) {
+		if (sh->log_start == log->last_checkpoint)
+			BUG();
+		else
+			r5l_add_no_space_stripe(log, sh);
 	} else {
 		ret = r5l_log_stripe(log, sh, pages, 0);
 		if (ret) {
@@ -1470,7 +1814,6 @@ r5c_cache_data(struct r5l_log *log, struct stripe_head *sh,
 	return 0;
 }
 
-
 static int r5l_load_log(struct r5l_log *log)
 {
 	struct md_rdev *rdev = log->rdev;
@@ -1530,6 +1873,9 @@ create:
 		log->max_free_space = RECLAIM_MAX_FREE_SPACE;
 	log->last_checkpoint = cp;
 	log->next_checkpoint = cp;
+	mutex_lock(&log->io_mutex);
+	r5c_update_log_state(log);
+	mutex_unlock(&log->io_mutex);
 
 	__free_page(page);
 
@@ -1601,6 +1947,8 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 						 log->rdev->mddev, "reclaim");
 	if (!log->reclaim_thread)
 		goto reclaim_thread;
+	log->reclaim_thread->timeout = R5C_RECLAIM_WAKEUP_INTERVAL;
+
 	init_waitqueue_head(&log->iounit_wait);
 
 	INIT_LIST_HEAD(&log->no_mem_stripes);
@@ -1609,6 +1957,9 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 	spin_lock_init(&log->no_space_stripes_lock);
 
 	log->r5c_journal_mode = R5C_JOURNAL_MODE_WRITE_THROUGH;
+	INIT_LIST_HEAD(&log->stripe_in_journal_list);
+	spin_lock_init(&log->stripe_in_journal_lock);
+	atomic_set(&log->stripe_in_journal_count, 0);
 
 	if (r5l_load_log(log))
 		goto error;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index f535ce2c267a..90638ba67812 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -228,6 +228,16 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 		for (i = sh->disks; i--; )
 			if (test_bit(R5_InJournal, &sh->dev[i].flags))
 				injournal++;
+	/*
+	 * When quiesce in r5c write back, set STRIPE_HANDLE for stripes with
+	 * data in journal, so they are not released to cached lists
+	 */
+	if (conf->quiesce && r5c_is_writeback(conf->log) &&
+	    !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0) {
+		if (test_bit(STRIPE_R5C_CACHING, &sh->state))
+			r5c_make_stripe_write_out(sh);
+		set_bit(STRIPE_HANDLE, &sh->state);
+	}
 
 	if (test_bit(STRIPE_HANDLE, &sh->state)) {
 		if (test_bit(STRIPE_DELAYED, &sh->state) &&
@@ -268,6 +278,7 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 					if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 						atomic_dec(&conf->r5c_cached_partial_stripes);
 					list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
+					r5c_check_cached_full_stripe(conf);
 				} else {
 					/* partial stripe */
 					if (!test_and_set_bit(STRIPE_R5C_PARTIAL_STRIPE,
@@ -639,9 +650,12 @@ raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 			}
 			if (noblock && sh == NULL)
 				break;
+
+			r5c_check_stripe_cache_usage(conf);
 			if (!sh) {
 				set_bit(R5_INACTIVE_BLOCKED,
 					&conf->cache_state);
+				r5l_wake_reclaim(conf->log, 0);
 				wait_event_lock_irq(
 					conf->wait_for_stripe,
 					!list_empty(conf->inactive_list + hash) &&
@@ -1992,7 +2006,9 @@ static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
 		spin_lock_init(&sh->batch_lock);
 		INIT_LIST_HEAD(&sh->batch_list);
 		INIT_LIST_HEAD(&sh->lru);
+		INIT_LIST_HEAD(&sh->r5c);
 		atomic_set(&sh->count, 1);
+		sh->log_start = MaxSector;
 		for (i = 0; i < disks; i++) {
 			struct r5dev *dev = &sh->dev[i];
 
@@ -4759,6 +4775,10 @@ static int raid5_congested(struct mddev *mddev, int bits)
 
 	if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 		return 1;
+
+	/* Also checks whether there is pressure on r5cache log space */
+	if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
+		return 1;
 	if (conf->quiesce)
 		return 1;
 	if (atomic_read(&conf->empty_inactive_list_nr))
@@ -7661,6 +7681,7 @@ static void raid5_quiesce(struct mddev *mddev, int state)
 		/* '2' tells resync/reshape to pause so that all
 		 * active stripes can drain
 		 */
+		r5c_flush_cache(conf, INT_MAX);
 		conf->quiesce = 2;
 		wait_event_cmd(conf->wait_for_quiescent,
 				    atomic_read(&conf->active_stripes) == 0 &&
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 73c183398e38..35b4c0f0a850 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -226,6 +226,8 @@ struct stripe_head {
 
 	struct r5l_io_unit	*log_io;
 	struct list_head	log_list;
+	sector_t		log_start; /* first meta block on the journal */
+	struct list_head	r5c; /* for r5c_cache->stripe_in_journal */
 	/**
 	 * struct stripe_operations
 	 * @target - STRIPE_OP_COMPUTE_BLK target
@@ -537,6 +539,27 @@ struct r5worker_group {
 	int stripes_cnt;
 };
 
+enum r5_cache_state {
+	R5_INACTIVE_BLOCKED,	/* release of inactive stripes blocked,
+				 * waiting for 25% to be free
+				 */
+	R5_ALLOC_MORE,		/* It might help to allocate another
+				 * stripe.
+				 */
+	R5_DID_ALLOC,		/* A stripe was allocated, don't allocate
+				 * more until at least one has been
+				 * released.  This avoids flooding
+				 * the cache.
+				 */
+	R5C_LOG_TIGHT,		/* log device space tight, need to
+				 * prioritize stripes at last_checkpoint
+				 */
+	R5C_LOG_CRITICAL,	/* log device is running out of space,
+				 * only process stripes that are already
+				 * occupying the log
+				 */
+};
+
 struct r5conf {
 	struct hlist_head	*stripe_hashtbl;
 	/* only protect corresponding hash list and inactive_list */
@@ -636,17 +659,6 @@ struct r5conf {
 	wait_queue_head_t	wait_for_stripe;
 	wait_queue_head_t	wait_for_overlap;
 	unsigned long		cache_state;
-#define R5_INACTIVE_BLOCKED	1	/* release of inactive stripes blocked,
-					 * waiting for 25% to be free
-					 */
-#define R5_ALLOC_MORE		2	/* It might help to allocate another
-					 * stripe.
-					 */
-#define R5_DID_ALLOC		4	/* A stripe was allocated, don't allocate
-					 * more until at least one has been
-					 * released.  This avoids flooding
-					 * the cache.
-					 */
 	struct shrinker		shrinker;
 	int			pool_size; /* number of disks in stripeheads in pool */
 	spinlock_t		device_lock;
@@ -752,8 +764,13 @@ extern void
 r5c_finish_stripe_write_out(struct r5conf *conf, struct stripe_head *sh,
 			    struct stripe_head_state *s);
 extern void r5c_release_extra_page(struct stripe_head *sh);
+extern void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
 extern void r5c_handle_cached_data_endio(struct r5conf *conf,
 	struct stripe_head *sh, int disks, struct bio_list *return_bi);
 extern int r5c_cache_data(struct r5l_log *log, struct stripe_head *sh,
 			  struct stripe_head_state *s);
+extern void r5c_make_stripe_write_out(struct stripe_head *sh);
+extern void r5c_flush_cache(struct r5conf *conf, int num);
+extern void r5c_check_stripe_cache_usage(struct r5conf *conf);
+extern void r5c_check_cached_full_stripe(struct r5conf *conf);
 #endif