1 files changed, 155 insertions, 12 deletions

diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
index 628c0bf7b9fd..2764c2290062 100644
--- a/drivers/md/raid5-ppl.c
+++ b/drivers/md/raid5-ppl.c
@@ -85,6 +85,9 @@
  * (for a single member disk). New io_units are added to the end of the list
  * and the first io_unit is submitted, if it is not submitted already.
  * The current io_unit accepting new stripes is always at the end of the list.
+ *
+ * If write-back cache is enabled for any of the disks in the array, its data
+ * must be flushed before next io_unit is submitted.
  */
 
 #define PPL_SPACE_SIZE (128 * 1024)
@@ -104,6 +107,7 @@ struct ppl_conf {
 	struct kmem_cache *io_kc;
 	mempool_t *io_pool;
 	struct bio_set *bs;
+	struct bio_set *flush_bs;
 
 	/* used only for recovery */
 	int recovered_entries;
@@ -128,6 +132,8 @@ struct ppl_log {
 	sector_t next_io_sector;
 	unsigned int entry_space;
 	bool use_multippl;
+	bool wb_cache_on;
+	unsigned long disk_flush_bitmap;
 };
 
 #define PPL_IO_INLINE_BVECS 32
@@ -145,6 +151,7 @@ struct ppl_io_unit {
 
 	struct list_head stripe_list;	/* stripes added to the io_unit */
 	atomic_t pending_stripes;	/* how many stripes not written to raid */
+	atomic_t pending_flushes;	/* how many disk flushes are in progress */
 
 	bool submitted;			/* true if write to log started */
 
@@ -249,6 +256,7 @@ static struct ppl_io_unit *ppl_new_iounit(struct ppl_log *log,
 	INIT_LIST_HEAD(&io->log_sibling);
 	INIT_LIST_HEAD(&io->stripe_list);
 	atomic_set(&io->pending_stripes, 0);
+	atomic_set(&io->pending_flushes, 0);
 	bio_init(&io->bio, io->biovec, PPL_IO_INLINE_BVECS);
 
 	pplhdr = page_address(io->header_page);
@@ -475,7 +483,18 @@ static void ppl_submit_iounit(struct ppl_io_unit *io)
 	if (log->use_multippl)
 		log->next_io_sector += (PPL_HEADER_SIZE + io->pp_size) >> 9;
 
+	WARN_ON(log->disk_flush_bitmap != 0);
+
 	list_for_each_entry(sh, &io->stripe_list, log_list) {
+		for (i = 0; i < sh->disks; i++) {
+			struct r5dev *dev = &sh->dev[i];
+
+			if ((ppl_conf->child_logs[i].wb_cache_on) &&
+			    (test_bit(R5_Wantwrite, &dev->flags))) {
+				set_bit(i, &log->disk_flush_bitmap);
+			}
+		}
+
 		/* entries for full stripe writes have no partial parity */
 		if (test_bit(STRIPE_FULL_WRITE, &sh->state))
 			continue;
@@ -540,6 +559,7 @@ static void ppl_io_unit_finished(struct ppl_io_unit *io)
 {
 	struct ppl_log *log = io->log;
 	struct ppl_conf *ppl_conf = log->ppl_conf;
+	struct r5conf *conf = ppl_conf->mddev->private;
 	unsigned long flags;
 
 	pr_debug("%s: seq: %llu\n", __func__, io->seq);
@@ -565,6 +585,112 @@ static void ppl_io_unit_finished(struct ppl_io_unit *io)
 	spin_unlock(&ppl_conf->no_mem_stripes_lock);
 
 	local_irq_restore(flags);
+
+	wake_up(&conf->wait_for_quiescent);
+}
+
+static void ppl_flush_endio(struct bio *bio)
+{
+	struct ppl_io_unit *io = bio->bi_private;
+	struct ppl_log *log = io->log;
+	struct ppl_conf *ppl_conf = log->ppl_conf;
+	struct r5conf *conf = ppl_conf->mddev->private;
+	char b[BDEVNAME_SIZE];
+
+	pr_debug("%s: dev: %s\n", __func__, bio_devname(bio, b));
+
+	if (bio->bi_status) {
+		struct md_rdev *rdev;
+
+		rcu_read_lock();
+		rdev = md_find_rdev_rcu(conf->mddev, bio_dev(bio));
+		if (rdev)
+			md_error(rdev->mddev, rdev);
+		rcu_read_unlock();
+	}
+
+	bio_put(bio);
+
+	if (atomic_dec_and_test(&io->pending_flushes)) {
+		ppl_io_unit_finished(io);
+		md_wakeup_thread(conf->mddev->thread);
+	}
+}
+
+static void ppl_do_flush(struct ppl_io_unit *io)
+{
+	struct ppl_log *log = io->log;
+	struct ppl_conf *ppl_conf = log->ppl_conf;
+	struct r5conf *conf = ppl_conf->mddev->private;
+	int raid_disks = conf->raid_disks;
+	int flushed_disks = 0;
+	int i;
+
+	atomic_set(&io->pending_flushes, raid_disks);
+
+	for_each_set_bit(i, &log->disk_flush_bitmap, raid_disks) {
+		struct md_rdev *rdev;
+		struct block_device *bdev = NULL;
+
+		rcu_read_lock();
+		rdev = rcu_dereference(conf->disks[i].rdev);
+		if (rdev && !test_bit(Faulty, &rdev->flags))
+			bdev = rdev->bdev;
+		rcu_read_unlock();
+
+		if (bdev) {
+			struct bio *bio;
+			char b[BDEVNAME_SIZE];
+
+			bio = bio_alloc_bioset(GFP_NOIO, 0, ppl_conf->flush_bs);
+			bio_set_dev(bio, bdev);
+			bio->bi_private = io;
+			bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
+			bio->bi_end_io = ppl_flush_endio;
+
+			pr_debug("%s: dev: %s\n", __func__,
+				 bio_devname(bio, b));
+
+			submit_bio(bio);
+			flushed_disks++;
+		}
+	}
+
+	log->disk_flush_bitmap = 0;
+
+	for (i = flushed_disks ; i < raid_disks; i++) {
+		if (atomic_dec_and_test(&io->pending_flushes))
+			ppl_io_unit_finished(io);
+	}
+}
+
+static inline bool ppl_no_io_unit_submitted(struct r5conf *conf,
+					    struct ppl_log *log)
+{
+	struct ppl_io_unit *io;
+
+	io = list_first_entry_or_null(&log->io_list, struct ppl_io_unit,
+				      log_sibling);
+
+	return !io || !io->submitted;
+}
+
+void ppl_quiesce(struct r5conf *conf, int quiesce)
+{
+	struct ppl_conf *ppl_conf = conf->log_private;
+	int i;
+
+	if (quiesce) {
+		for (i = 0; i < ppl_conf->count; i++) {
+			struct ppl_log *log = &ppl_conf->child_logs[i];
+
+			spin_lock_irq(&log->io_list_lock);
+			wait_event_lock_irq(conf->wait_for_quiescent,
+					    ppl_no_io_unit_submitted(conf, log),
+					    log->io_list_lock);
+			spin_unlock_irq(&log->io_list_lock);
+		}
+	}
 }
 
 void ppl_stripe_write_finished(struct stripe_head *sh)
@@ -574,8 +700,12 @@ void ppl_stripe_write_finished(struct stripe_head *sh)
 	io = sh->ppl_io;
 	sh->ppl_io = NULL;
 
-	if (io && atomic_dec_and_test(&io->pending_stripes))
-		ppl_io_unit_finished(io);
+	if (io && atomic_dec_and_test(&io->pending_stripes)) {
+		if (io->log->disk_flush_bitmap)
+			ppl_do_flush(io);
+		else
+			ppl_io_unit_finished(io);
+	}
 }
 
 static void ppl_xor(int size, struct page *page1, struct page *page2)
@@ -1108,6 +1238,8 @@ static void __ppl_exit_log(struct ppl_conf *ppl_conf)
 
 	if (ppl_conf->bs)
 		bioset_free(ppl_conf->bs);
+	if (ppl_conf->flush_bs)
+		bioset_free(ppl_conf->flush_bs);
 	mempool_destroy(ppl_conf->io_pool);
 	kmem_cache_destroy(ppl_conf->io_kc);
 
@@ -1173,6 +1305,8 @@ static int ppl_validate_rdev(struct md_rdev *rdev)
 
 static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
 {
+	struct request_queue *q;
+
 	if ((rdev->ppl.size << 9) >= (PPL_SPACE_SIZE +
 				      PPL_HEADER_SIZE) * 2) {
 		log->use_multippl = true;
@@ -1185,6 +1319,10 @@ static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
 				   PPL_HEADER_SIZE;
 	}
 	log->next_io_sector = rdev->ppl.sector;
+
+	q = bdev_get_queue(rdev->bdev);
+	if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
+		log->wb_cache_on = true;
 }
 
 int ppl_init_log(struct r5conf *conf)
@@ -1192,8 +1330,8 @@ int ppl_init_log(struct r5conf *conf)
 	struct ppl_conf *ppl_conf;
 	struct mddev *mddev = conf->mddev;
 	int ret = 0;
+	int max_disks;
 	int i;
-	bool need_cache_flush = false;
 
 	pr_debug("md/raid:%s: enabling distributed Partial Parity Log\n",
 		 mdname(conf->mddev));
@@ -1219,6 +1357,14 @@ int ppl_init_log(struct r5conf *conf)
 		return -EINVAL;
 	}
 
+	max_disks = FIELD_SIZEOF(struct ppl_log, disk_flush_bitmap) *
+		BITS_PER_BYTE;
+	if (conf->raid_disks > max_disks) {
+		pr_warn("md/raid:%s PPL doesn't support over %d disks in the array\n",
+			mdname(mddev), max_disks);
+		return -EINVAL;
+	}
+
 	ppl_conf = kzalloc(sizeof(struct ppl_conf), GFP_KERNEL);
 	if (!ppl_conf)
 		return -ENOMEM;
@@ -1244,6 +1390,12 @@ int ppl_init_log(struct r5conf *conf)
 		goto err;
 	}
 
+	ppl_conf->flush_bs = bioset_create(conf->raid_disks, 0, 0);
+	if (!ppl_conf->flush_bs) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
 	ppl_conf->count = conf->raid_disks;
 	ppl_conf->child_logs = kcalloc(ppl_conf->count, sizeof(struct ppl_log),
 				       GFP_KERNEL);
@@ -1275,23 +1427,14 @@ int ppl_init_log(struct r5conf *conf)
 		log->rdev = rdev;
 
 		if (rdev) {
-			struct request_queue *q;
-
 			ret = ppl_validate_rdev(rdev);
 			if (ret)
 				goto err;
 
-			q = bdev_get_queue(rdev->bdev);
-			if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
-				need_cache_flush = true;
 			ppl_init_child_log(log, rdev);
 		}
 	}
 
-	if (need_cache_flush)
-		pr_warn("md/raid:%s: Volatile write-back cache should be disabled on all member drives when using PPL!\n",
-			mdname(mddev));
-
 	/* load and possibly recover the logs from the member disks */
 	ret = ppl_load(ppl_conf);