25 files changed, 2587 insertions, 3005 deletions

diff --git a/drivers/md/bcache/Kconfig b/drivers/md/bcache/Kconfig
index f950c9d29f3e..2638417b19aa 100644
--- a/drivers/md/bcache/Kconfig
+++ b/drivers/md/bcache/Kconfig
@@ -13,15 +13,8 @@ config BCACHE_DEBUG
 	---help---
 	Don't select this option unless you're a developer
 
-	Enables extra debugging tools (primarily a fuzz tester)
-
-config BCACHE_EDEBUG
-	bool "Extended runtime checks"
-	depends on BCACHE
-	---help---
-	Don't select this option unless you're a developer
-
-	Enables extra runtime checks which significantly affect performance
+	Enables extra debugging tools, allows expensive runtime checks to be
+	turned on.
 
 config BCACHE_CLOSURES_DEBUG
 	bool "Debug closures"
diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index e45f5575fd4d..2b46bf1d7e40 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -63,13 +63,12 @@
 #include "bcache.h"
 #include "btree.h"
 
+#include <linux/blkdev.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/random.h>
 #include <trace/events/bcache.h>
 
-#define MAX_IN_FLIGHT_DISCARDS		8U
-
 /* Bucket heap / gen */
 
 uint8_t bch_inc_gen(struct cache *ca, struct bucket *b)
@@ -121,75 +120,6 @@ void bch_rescale_priorities(struct cache_set *c, int sectors)
 	mutex_unlock(&c->bucket_lock);
 }
 
-/* Discard/TRIM */
-
-struct discard {
-	struct list_head	list;
-	struct work_struct	work;
-	struct cache		*ca;
-	long			bucket;
-
-	struct bio		bio;
-	struct bio_vec		bv;
-};
-
-static void discard_finish(struct work_struct *w)
-{
-	struct discard *d = container_of(w, struct discard, work);
-	struct cache *ca = d->ca;
-	char buf[BDEVNAME_SIZE];
-
-	if (!test_bit(BIO_UPTODATE, &d->bio.bi_flags)) {
-		pr_notice("discard error on %s, disabling",
-			 bdevname(ca->bdev, buf));
-		d->ca->discard = 0;
-	}
-
-	mutex_lock(&ca->set->bucket_lock);
-
-	fifo_push(&ca->free, d->bucket);
-	list_add(&d->list, &ca->discards);
-	atomic_dec(&ca->discards_in_flight);
-
-	mutex_unlock(&ca->set->bucket_lock);
-
-	closure_wake_up(&ca->set->bucket_wait);
-	wake_up_process(ca->alloc_thread);
-
-	closure_put(&ca->set->cl);
-}
-
-static void discard_endio(struct bio *bio, int error)
-{
-	struct discard *d = container_of(bio, struct discard, bio);
-	schedule_work(&d->work);
-}
-
-static void do_discard(struct cache *ca, long bucket)
-{
-	struct discard *d = list_first_entry(&ca->discards,
-					     struct discard, list);
-
-	list_del(&d->list);
-	d->bucket = bucket;
-
-	atomic_inc(&ca->discards_in_flight);
-	closure_get(&ca->set->cl);
-
-	bio_init(&d->bio);
-
-	d->bio.bi_sector	= bucket_to_sector(ca->set, d->bucket);
-	d->bio.bi_bdev		= ca->bdev;
-	d->bio.bi_rw		= REQ_WRITE|REQ_DISCARD;
-	d->bio.bi_max_vecs	= 1;
-	d->bio.bi_io_vec	= d->bio.bi_inline_vecs;
-	d->bio.bi_size		= bucket_bytes(ca);
-	d->bio.bi_end_io	= discard_endio;
-	bio_set_prio(&d->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
-
-	submit_bio(0, &d->bio);
-}
-
 /* Allocation */
 
 static inline bool can_inc_bucket_gen(struct bucket *b)
@@ -280,7 +210,7 @@ static void invalidate_buckets_lru(struct cache *ca)
 			 * multiple times when it can't do anything
 			 */
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 
@@ -305,7 +235,7 @@ static void invalidate_buckets_fifo(struct cache *ca)
 
 		if (++checked >= ca->sb.nbuckets) {
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 	}
@@ -330,7 +260,7 @@ static void invalidate_buckets_random(struct cache *ca)
 
 		if (++checked >= ca->sb.nbuckets / 2) {
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 	}
@@ -398,16 +328,18 @@ static int bch_allocator_thread(void *arg)
 			else
 				break;
 
-			allocator_wait(ca, (int) fifo_free(&ca->free) >
-				       atomic_read(&ca->discards_in_flight));
-
 			if (ca->discard) {
-				allocator_wait(ca, !list_empty(&ca->discards));
-				do_discard(ca, bucket);
-			} else {
-				fifo_push(&ca->free, bucket);
-				closure_wake_up(&ca->set->bucket_wait);
+				mutex_unlock(&ca->set->bucket_lock);
+				blkdev_issue_discard(ca->bdev,
+					bucket_to_sector(ca->set, bucket),
+					ca->sb.block_size, GFP_KERNEL, 0);
+				mutex_lock(&ca->set->bucket_lock);
 			}
+
+			allocator_wait(ca, !fifo_full(&ca->free));
+
+			fifo_push(&ca->free, bucket);
+			wake_up(&ca->set->bucket_wait);
 		}
 
 		/*
@@ -433,16 +365,40 @@ static int bch_allocator_thread(void *arg)
 	}
 }
 
-long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
+long bch_bucket_alloc(struct cache *ca, unsigned watermark, bool wait)
 {
-	long r = -1;
-again:
+	DEFINE_WAIT(w);
+	struct bucket *b;
+	long r;
+
+	/* fastpath */
+	if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+		fifo_pop(&ca->free, r);
+		goto out;
+	}
+
+	if (!wait)
+		return -1;
+
+	while (1) {
+		if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+			fifo_pop(&ca->free, r);
+			break;
+		}
+
+		prepare_to_wait(&ca->set->bucket_wait, &w,
+				TASK_UNINTERRUPTIBLE);
+
+		mutex_unlock(&ca->set->bucket_lock);
+		schedule();
+		mutex_lock(&ca->set->bucket_lock);
+	}
+
+	finish_wait(&ca->set->bucket_wait, &w);
+out:
 	wake_up_process(ca->alloc_thread);
 
-	if (fifo_used(&ca->free) > ca->watermark[watermark] &&
-	    fifo_pop(&ca->free, r)) {
-		struct bucket *b = ca->buckets + r;
-#ifdef CONFIG_BCACHE_EDEBUG
+	if (expensive_debug_checks(ca->set)) {
 		size_t iter;
 		long i;
 
@@ -455,36 +411,23 @@ again:
 			BUG_ON(i == r);
 		fifo_for_each(i, &ca->unused, iter)
 			BUG_ON(i == r);
-#endif
-		BUG_ON(atomic_read(&b->pin) != 1);
-
-		SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
-
-		if (watermark <= WATERMARK_METADATA) {
-			SET_GC_MARK(b, GC_MARK_METADATA);
-			b->prio = BTREE_PRIO;
-		} else {
-			SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
-			b->prio = INITIAL_PRIO;
-		}
-
-		return r;
 	}
 
-	trace_bcache_alloc_fail(ca);
+	b = ca->buckets + r;
 
-	if (cl) {
-		closure_wait(&ca->set->bucket_wait, cl);
+	BUG_ON(atomic_read(&b->pin) != 1);
 
-		if (closure_blocking(cl)) {
-			mutex_unlock(&ca->set->bucket_lock);
-			closure_sync(cl);
-			mutex_lock(&ca->set->bucket_lock);
-			goto again;
-		}
+	SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
+
+	if (watermark <= WATERMARK_METADATA) {
+		SET_GC_MARK(b, GC_MARK_METADATA);
+		b->prio = BTREE_PRIO;
+	} else {
+		SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
+		b->prio = INITIAL_PRIO;
 	}
 
-	return -1;
+	return r;
 }
 
 void bch_bucket_free(struct cache_set *c, struct bkey *k)
@@ -501,7 +444,7 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k)
 }
 
 int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-			   struct bkey *k, int n, struct closure *cl)
+			   struct bkey *k, int n, bool wait)
 {
 	int i;
 
@@ -514,7 +457,7 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 
 	for (i = 0; i < n; i++) {
 		struct cache *ca = c->cache_by_alloc[i];
-		long b = bch_bucket_alloc(ca, watermark, cl);
+		long b = bch_bucket_alloc(ca, watermark, wait);
 
 		if (b == -1)
 			goto err;
@@ -529,22 +472,202 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 	return 0;
 err:
 	bch_bucket_free(c, k);
-	__bkey_put(c, k);
+	bkey_put(c, k);
 	return -1;
 }
 
 int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-			 struct bkey *k, int n, struct closure *cl)
+			 struct bkey *k, int n, bool wait)
 {
 	int ret;
 	mutex_lock(&c->bucket_lock);
-	ret = __bch_bucket_alloc_set(c, watermark, k, n, cl);
+	ret = __bch_bucket_alloc_set(c, watermark, k, n, wait);
 	mutex_unlock(&c->bucket_lock);
 	return ret;
 }
 
+/* Sector allocator */
+
+struct open_bucket {
+	struct list_head	list;
+	unsigned		last_write_point;
+	unsigned		sectors_free;
+	BKEY_PADDED(key);
+};
+
+/*
+ * We keep multiple buckets open for writes, and try to segregate different
+ * write streams for better cache utilization: first we look for a bucket where
+ * the last write to it was sequential with the current write, and failing that
+ * we look for a bucket that was last used by the same task.
+ *
+ * The ideas is if you've got multiple tasks pulling data into the cache at the
+ * same time, you'll get better cache utilization if you try to segregate their
+ * data and preserve locality.
+ *
+ * For example, say you've starting Firefox at the same time you're copying a
+ * bunch of files. Firefox will likely end up being fairly hot and stay in the
+ * cache awhile, but the data you copied might not be; if you wrote all that
+ * data to the same buckets it'd get invalidated at the same time.
+ *
+ * Both of those tasks will be doing fairly random IO so we can't rely on
+ * detecting sequential IO to segregate their data, but going off of the task
+ * should be a sane heuristic.
+ */
+static struct open_bucket *pick_data_bucket(struct cache_set *c,
+					    const struct bkey *search,
+					    unsigned write_point,
+					    struct bkey *alloc)
+{
+	struct open_bucket *ret, *ret_task = NULL;
+
+	list_for_each_entry_reverse(ret, &c->data_buckets, list)
+		if (!bkey_cmp(&ret->key, search))
+			goto found;
+		else if (ret->last_write_point == write_point)
+			ret_task = ret;
+
+	ret = ret_task ?: list_first_entry(&c->data_buckets,
+					   struct open_bucket, list);
+found:
+	if (!ret->sectors_free && KEY_PTRS(alloc)) {
+		ret->sectors_free = c->sb.bucket_size;
+		bkey_copy(&ret->key, alloc);
+		bkey_init(alloc);
+	}
+
+	if (!ret->sectors_free)
+		ret = NULL;
+
+	return ret;
+}
+
+/*
+ * Allocates some space in the cache to write to, and k to point to the newly
+ * allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
+ * end of the newly allocated space).
+ *
+ * May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
+ * sectors were actually allocated.
+ *
+ * If s->writeback is true, will not fail.
+ */
+bool bch_alloc_sectors(struct cache_set *c, struct bkey *k, unsigned sectors,
+		       unsigned write_point, unsigned write_prio, bool wait)
+{
+	struct open_bucket *b;
+	BKEY_PADDED(key) alloc;
+	unsigned i;
+
+	/*
+	 * We might have to allocate a new bucket, which we can't do with a
+	 * spinlock held. So if we have to allocate, we drop the lock, allocate
+	 * and then retry. KEY_PTRS() indicates whether alloc points to
+	 * allocated bucket(s).
+	 */
+
+	bkey_init(&alloc.key);
+	spin_lock(&c->data_bucket_lock);
+
+	while (!(b = pick_data_bucket(c, k, write_point, &alloc.key))) {
+		unsigned watermark = write_prio
+			? WATERMARK_MOVINGGC
+			: WATERMARK_NONE;
+
+		spin_unlock(&c->data_bucket_lock);
+
+		if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, wait))
+			return false;
+
+		spin_lock(&c->data_bucket_lock);
+	}
+
+	/*
+	 * If we had to allocate, we might race and not need to allocate the
+	 * second time we call find_data_bucket(). If we allocated a bucket but
+	 * didn't use it, drop the refcount bch_bucket_alloc_set() took:
+	 */
+	if (KEY_PTRS(&alloc.key))
+		bkey_put(c, &alloc.key);
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++)
+		EBUG_ON(ptr_stale(c, &b->key, i));
+
+	/* Set up the pointer to the space we're allocating: */
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++)
+		k->ptr[i] = b->key.ptr[i];
+
+	sectors = min(sectors, b->sectors_free);
+
+	SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
+	SET_KEY_SIZE(k, sectors);
+	SET_KEY_PTRS(k, KEY_PTRS(&b->key));
+
+	/*
+	 * Move b to the end of the lru, and keep track of what this bucket was
+	 * last used for:
+	 */
+	list_move_tail(&b->list, &c->data_buckets);
+	bkey_copy_key(&b->key, k);
+	b->last_write_point = write_point;
+
+	b->sectors_free	-= sectors;
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++) {
+		SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
+
+		atomic_long_add(sectors,
+				&PTR_CACHE(c, &b->key, i)->sectors_written);
+	}
+
+	if (b->sectors_free < c->sb.block_size)
+		b->sectors_free = 0;
+
+	/*
+	 * k takes refcounts on the buckets it points to until it's inserted
+	 * into the btree, but if we're done with this bucket we just transfer
+	 * get_data_bucket()'s refcount.
+	 */
+	if (b->sectors_free)
+		for (i = 0; i < KEY_PTRS(&b->key); i++)
+			atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
+
+	spin_unlock(&c->data_bucket_lock);
+	return true;
+}
+
 /* Init */
 
+void bch_open_buckets_free(struct cache_set *c)
+{
+	struct open_bucket *b;
+
+	while (!list_empty(&c->data_buckets)) {
+		b = list_first_entry(&c->data_buckets,
+				     struct open_bucket, list);
+		list_del(&b->list);
+		kfree(b);
+	}
+}
+
+int bch_open_buckets_alloc(struct cache_set *c)
+{
+	int i;
+
+	spin_lock_init(&c->data_bucket_lock);
+
+	for (i = 0; i < 6; i++) {
+		struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
+		if (!b)
+			return -ENOMEM;
+
+		list_add(&b->list, &c->data_buckets);
+	}
+
+	return 0;
+}
+
 int bch_cache_allocator_start(struct cache *ca)
 {
 	struct task_struct *k = kthread_run(bch_allocator_thread,
@@ -556,22 +679,8 @@ int bch_cache_allocator_start(struct cache *ca)
 	return 0;
 }
 
-void bch_cache_allocator_exit(struct cache *ca)
-{
-	struct discard *d;
-
-	while (!list_empty(&ca->discards)) {
-		d = list_first_entry(&ca->discards, struct discard, list);
-		cancel_work_sync(&d->work);
-		list_del(&d->list);
-		kfree(d);
-	}
-}
-
 int bch_cache_allocator_init(struct cache *ca)
 {
-	unsigned i;
-
 	/*
 	 * Reserve:
 	 * Prio/gen writes first
@@ -589,15 +698,5 @@ int bch_cache_allocator_init(struct cache *ca)
 	ca->watermark[WATERMARK_NONE] = ca->free.size / 2 +
 		ca->watermark[WATERMARK_MOVINGGC];
 
-	for (i = 0; i < MAX_IN_FLIGHT_DISCARDS; i++) {
-		struct discard *d = kzalloc(sizeof(*d), GFP_KERNEL);
-		if (!d)
-			return -ENOMEM;
-
-		d->ca = ca;
-		INIT_WORK(&d->work, discard_finish);
-		list_add(&d->list, &ca->discards);
-	}
-
 	return 0;
 }
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 0f12382aa35d..4beb55a0ff30 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -177,6 +177,7 @@
 
 #define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
 
+#include <linux/bcache.h>
 #include <linux/bio.h>
 #include <linux/kobject.h>
 #include <linux/list.h>
@@ -210,168 +211,6 @@ BITMASK(GC_MARK,	 struct bucket, gc_mark, 0, 2);
 #define GC_MARK_METADATA	2
 BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, 14);
 
-struct bkey {
-	uint64_t	high;
-	uint64_t	low;
-	uint64_t	ptr[];
-};
-
-/* Enough for a key with 6 pointers */
-#define BKEY_PAD		8
-
-#define BKEY_PADDED(key)					\
-	union { struct bkey key; uint64_t key ## _pad[BKEY_PAD]; }
-
-/* Version 0: Cache device
- * Version 1: Backing device
- * Version 2: Seed pointer into btree node checksum
- * Version 3: Cache device with new UUID format
- * Version 4: Backing device with data offset
- */
-#define BCACHE_SB_VERSION_CDEV			0
-#define BCACHE_SB_VERSION_BDEV			1
-#define BCACHE_SB_VERSION_CDEV_WITH_UUID	3
-#define BCACHE_SB_VERSION_BDEV_WITH_OFFSET	4
-#define BCACHE_SB_MAX_VERSION			4
-
-#define SB_SECTOR		8
-#define SB_SIZE			4096
-#define SB_LABEL_SIZE		32
-#define SB_JOURNAL_BUCKETS	256U
-/* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
-#define MAX_CACHES_PER_SET	8
-
-#define BDEV_DATA_START_DEFAULT	16	/* sectors */
-
-struct cache_sb {
-	uint64_t		csum;
-	uint64_t		offset;	/* sector where this sb was written */
-	uint64_t		version;
-
-	uint8_t			magic[16];
-
-	uint8_t			uuid[16];
-	union {
-		uint8_t		set_uuid[16];
-		uint64_t	set_magic;
-	};
-	uint8_t			label[SB_LABEL_SIZE];
-
-	uint64_t		flags;
-	uint64_t		seq;
-	uint64_t		pad[8];
-
-	union {
-	struct {
-		/* Cache devices */
-		uint64_t	nbuckets;	/* device size */
-
-		uint16_t	block_size;	/* sectors */
-		uint16_t	bucket_size;	/* sectors */
-
-		uint16_t	nr_in_set;
-		uint16_t	nr_this_dev;
-	};
-	struct {
-		/* Backing devices */
-		uint64_t	data_offset;
-
-		/*
-		 * block_size from the cache device section is still used by
-		 * backing devices, so don't add anything here until we fix
-		 * things to not need it for backing devices anymore
-		 */
-	};
-	};
-
-	uint32_t		last_mount;	/* time_t */
-
-	uint16_t		first_bucket;
-	union {
-		uint16_t	njournal_buckets;
-		uint16_t	keys;
-	};
-	uint64_t		d[SB_JOURNAL_BUCKETS];	/* journal buckets */
-};
-
-BITMASK(CACHE_SYNC,		struct cache_sb, flags, 0, 1);
-BITMASK(CACHE_DISCARD,		struct cache_sb, flags, 1, 1);
-BITMASK(CACHE_REPLACEMENT,	struct cache_sb, flags, 2, 3);
-#define CACHE_REPLACEMENT_LRU	0U
-#define CACHE_REPLACEMENT_FIFO	1U
-#define CACHE_REPLACEMENT_RANDOM 2U
-
-BITMASK(BDEV_CACHE_MODE,	struct cache_sb, flags, 0, 4);
-#define CACHE_MODE_WRITETHROUGH	0U
-#define CACHE_MODE_WRITEBACK	1U
-#define CACHE_MODE_WRITEAROUND	2U
-#define CACHE_MODE_NONE		3U
-BITMASK(BDEV_STATE,		struct cache_sb, flags, 61, 2);
-#define BDEV_STATE_NONE		0U
-#define BDEV_STATE_CLEAN	1U
-#define BDEV_STATE_DIRTY	2U
-#define BDEV_STATE_STALE	3U
-
-/* Version 1: Seed pointer into btree node checksum
- */
-#define BCACHE_BSET_VERSION	1
-
-/*
- * This is the on disk format for btree nodes - a btree node on disk is a list
- * of these; within each set the keys are sorted
- */
-struct bset {
-	uint64_t		csum;
-	uint64_t		magic;
-	uint64_t		seq;
-	uint32_t		version;
-	uint32_t		keys;
-
-	union {
-		struct bkey	start[0];
-		uint64_t	d[0];
-	};
-};
-
-/*
- * On disk format for priorities and gens - see super.c near prio_write() for
- * more.
- */
-struct prio_set {
-	uint64_t		csum;
-	uint64_t		magic;
-	uint64_t		seq;
-	uint32_t		version;
-	uint32_t		pad;
-
-	uint64_t		next_bucket;
-
-	struct bucket_disk {
-		uint16_t	prio;
-		uint8_t		gen;
-	} __attribute((packed)) data[];
-};
-
-struct uuid_entry {
-	union {
-		struct {
-			uint8_t		uuid[16];
-			uint8_t		label[32];
-			uint32_t	first_reg;
-			uint32_t	last_reg;
-			uint32_t	invalidated;
-
-			uint32_t	flags;
-			/* Size of flash only volumes */
-			uint64_t	sectors;
-		};
-
-		uint8_t	pad[128];
-	};
-};
-
-BITMASK(UUID_FLASH_ONLY,	struct uuid_entry, flags, 0, 1);
-
 #include "journal.h"
 #include "stats.h"
 struct search;
@@ -384,8 +223,6 @@ struct keybuf_key {
 	void			*private;
 };
 
-typedef bool (keybuf_pred_fn)(struct keybuf *, struct bkey *);
-
 struct keybuf {
 	struct bkey		last_scanned;
 	spinlock_t		lock;
@@ -400,7 +237,7 @@ struct keybuf {
 
 	struct rb_root		keys;
 
-#define KEYBUF_NR		100
+#define KEYBUF_NR		500
 	DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR);
 };
 
@@ -429,16 +266,15 @@ struct bcache_device {
 
 	struct gendisk		*disk;
 
-	/* If nonzero, we're closing */
-	atomic_t		closing;
-
-	/* If nonzero, we're detaching/unregistering from cache set */
-	atomic_t		detaching;
-	int			flush_done;
+	unsigned long		flags;
+#define BCACHE_DEV_CLOSING	0
+#define BCACHE_DEV_DETACHING	1
+#define BCACHE_DEV_UNLINK_DONE	2
 
-	uint64_t		nr_stripes;
-	unsigned		stripe_size_bits;
+	unsigned		nr_stripes;
+	unsigned		stripe_size;
 	atomic_t		*stripe_sectors_dirty;
+	unsigned long		*full_dirty_stripes;
 
 	unsigned long		sectors_dirty_last;
 	long			sectors_dirty_derivative;
@@ -509,7 +345,7 @@ struct cached_dev {
 
 	/* Limit number of writeback bios in flight */
 	struct semaphore	in_flight;
-	struct closure_with_timer writeback;
+	struct task_struct	*writeback_thread;
 
 	struct keybuf		writeback_keys;
 
@@ -527,8 +363,8 @@ struct cached_dev {
 	unsigned		sequential_cutoff;
 	unsigned		readahead;
 
-	unsigned		sequential_merge:1;
 	unsigned		verify:1;
+	unsigned		bypass_torture_test:1;
 
 	unsigned		partial_stripes_expensive:1;
 	unsigned		writeback_metadata:1;
@@ -620,15 +456,6 @@ struct cache {
 
 	bool			discard; /* Get rid of? */
 
-	/*
-	 * We preallocate structs for issuing discards to buckets, and keep them
-	 * on this list when they're not in use; do_discard() issues discards
-	 * whenever there's work to do and is called by free_some_buckets() and
-	 * when a discard finishes.
-	 */
-	atomic_t		discards_in_flight;
-	struct list_head	discards;
-
 	struct journal_device	journal;
 
 	/* The rest of this all shows up in sysfs */
@@ -649,7 +476,6 @@ struct gc_stat {
 
 	size_t			nkeys;
 	uint64_t		data;	/* sectors */
-	uint64_t		dirty;	/* sectors */
 	unsigned		in_use; /* percent */
 };
 
@@ -744,8 +570,8 @@ struct cache_set {
 	 * basically a lock for this that we can wait on asynchronously. The
 	 * btree_root() macro releases the lock when it returns.
 	 */
-	struct closure		*try_harder;
-	struct closure_waitlist	try_wait;
+	struct task_struct	*try_harder;
+	wait_queue_head_t	try_wait;
 	uint64_t		try_harder_start;
 
 	/*
@@ -759,7 +585,7 @@ struct cache_set {
 	 * written.
 	 */
 	atomic_t		prio_blocked;
-	struct closure_waitlist	bucket_wait;
+	wait_queue_head_t	bucket_wait;
 
 	/*
 	 * For any bio we don't skip we subtract the number of sectors from
@@ -782,7 +608,7 @@ struct cache_set {
 	struct gc_stat		gc_stats;
 	size_t			nbuckets;
 
-	struct closure_with_waitlist gc;
+	struct task_struct	*gc_thread;
 	/* Where in the btree gc currently is */
 	struct bkey		gc_done;
 
@@ -795,11 +621,10 @@ struct cache_set {
 	/* Counts how many sectors bio_insert has added to the cache */
 	atomic_t		sectors_to_gc;
 
-	struct closure		moving_gc;
-	struct closure_waitlist	moving_gc_wait;
+	wait_queue_head_t	moving_gc_wait;
 	struct keybuf		moving_gc_keys;
 	/* Number of moving GC bios in flight */
-	atomic_t		in_flight;
+	struct semaphore	moving_in_flight;
 
 	struct btree		*root;
 
@@ -841,22 +666,27 @@ struct cache_set {
 	unsigned		congested_read_threshold_us;
 	unsigned		congested_write_threshold_us;
 
-	spinlock_t		sort_time_lock;
 	struct time_stats	sort_time;
 	struct time_stats	btree_gc_time;
 	struct time_stats	btree_split_time;
-	spinlock_t		btree_read_time_lock;
 	struct time_stats	btree_read_time;
 	struct time_stats	try_harder_time;
 
 	atomic_long_t		cache_read_races;
 	atomic_long_t		writeback_keys_done;
 	atomic_long_t		writeback_keys_failed;
+
+	enum			{
+		ON_ERROR_UNREGISTER,
+		ON_ERROR_PANIC,
+	}			on_error;
 	unsigned		error_limit;
 	unsigned		error_decay;
+
 	unsigned short		journal_delay_ms;
 	unsigned		verify:1;
 	unsigned		key_merging_disabled:1;
+	unsigned		expensive_debug_checks:1;
 	unsigned		gc_always_rewrite:1;
 	unsigned		shrinker_disabled:1;
 	unsigned		copy_gc_enabled:1;
@@ -865,21 +695,6 @@ struct cache_set {
 	struct hlist_head	bucket_hash[1 << BUCKET_HASH_BITS];
 };
 
-static inline bool key_merging_disabled(struct cache_set *c)
-{
-#ifdef CONFIG_BCACHE_DEBUG
-	return c->key_merging_disabled;
-#else
-	return 0;
-#endif
-}
-
-static inline bool SB_IS_BDEV(const struct cache_sb *sb)
-{
-	return sb->version == BCACHE_SB_VERSION_BDEV
-		|| sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
-}
-
 struct bbio {
 	unsigned		submit_time_us;
 	union {
@@ -933,59 +748,6 @@ static inline unsigned local_clock_us(void)
 #define prio_buckets(c)					\
 	DIV_ROUND_UP((size_t) (c)->sb.nbuckets, prios_per_bucket(c))
 
-#define JSET_MAGIC		0x245235c1a3625032ULL
-#define PSET_MAGIC		0x6750e15f87337f91ULL
-#define BSET_MAGIC		0x90135c78b99e07f5ULL
-
-#define jset_magic(c)		((c)->sb.set_magic ^ JSET_MAGIC)
-#define pset_magic(c)		((c)->sb.set_magic ^ PSET_MAGIC)
-#define bset_magic(c)		((c)->sb.set_magic ^ BSET_MAGIC)
-
-/* Bkey fields: all units are in sectors */
-
-#define KEY_FIELD(name, field, offset, size)				\
-	BITMASK(name, struct bkey, field, offset, size)
-
-#define PTR_FIELD(name, offset, size)					\
-	static inline uint64_t name(const struct bkey *k, unsigned i)	\
-	{ return (k->ptr[i] >> offset) & ~(((uint64_t) ~0) << size); }	\
-									\
-	static inline void SET_##name(struct bkey *k, unsigned i, uint64_t v)\
-	{								\
-		k->ptr[i] &= ~(~((uint64_t) ~0 << size) << offset);	\
-		k->ptr[i] |= v << offset;				\
-	}
-
-KEY_FIELD(KEY_PTRS,	high, 60, 3)
-KEY_FIELD(HEADER_SIZE,	high, 58, 2)
-KEY_FIELD(KEY_CSUM,	high, 56, 2)
-KEY_FIELD(KEY_PINNED,	high, 55, 1)
-KEY_FIELD(KEY_DIRTY,	high, 36, 1)
-
-KEY_FIELD(KEY_SIZE,	high, 20, 16)
-KEY_FIELD(KEY_INODE,	high, 0,  20)
-
-/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
-
-static inline uint64_t KEY_OFFSET(const struct bkey *k)
-{
-	return k->low;
-}
-
-static inline void SET_KEY_OFFSET(struct bkey *k, uint64_t v)
-{
-	k->low = v;
-}
-
-PTR_FIELD(PTR_DEV,		51, 12)
-PTR_FIELD(PTR_OFFSET,		8,  43)
-PTR_FIELD(PTR_GEN,		0,  8)
-
-#define PTR_CHECK_DEV		((1 << 12) - 1)
-
-#define PTR(gen, offset, dev)						\
-	((((uint64_t) dev) << 51) | ((uint64_t) offset) << 8 | gen)
-
 static inline size_t sector_to_bucket(struct cache_set *c, sector_t s)
 {
 	return s >> c->bucket_bits;
@@ -1024,27 +786,11 @@ static inline struct bucket *PTR_BUCKET(struct cache_set *c,
 
 /* Btree key macros */
 
-/*
- * The high bit being set is a relic from when we used it to do binary
- * searches - it told you where a key started. It's not used anymore,
- * and can probably be safely dropped.
- */
-#define KEY(dev, sector, len)						\
-((struct bkey) {							\
-	.high = (1ULL << 63) | ((uint64_t) (len) << 20) | (dev),	\
-	.low = (sector)							\
-})
-
 static inline void bkey_init(struct bkey *k)
 {
-	*k = KEY(0, 0, 0);
+	*k = ZERO_KEY;
 }
 
-#define KEY_START(k)		(KEY_OFFSET(k) - KEY_SIZE(k))
-#define START_KEY(k)		KEY(KEY_INODE(k), KEY_START(k), 0)
-#define MAX_KEY			KEY(~(~0 << 20), ((uint64_t) ~0) >> 1, 0)
-#define ZERO_KEY		KEY(0, 0, 0)
-
 /*
  * This is used for various on disk data structures - cache_sb, prio_set, bset,
  * jset: The checksum is _always_ the first 8 bytes of these structs
@@ -1094,14 +840,6 @@ do {									\
 	for (b = (ca)->buckets + (ca)->sb.first_bucket;			\
 	     b < (ca)->buckets + (ca)->sb.nbuckets; b++)
 
-static inline void __bkey_put(struct cache_set *c, struct bkey *k)
-{
-	unsigned i;
-
-	for (i = 0; i < KEY_PTRS(k); i++)
-		atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
-}
-
 static inline void cached_dev_put(struct cached_dev *dc)
 {
 	if (atomic_dec_and_test(&dc->count))
@@ -1173,13 +911,15 @@ uint8_t bch_inc_gen(struct cache *, struct bucket *);
 void bch_rescale_priorities(struct cache_set *, int);
 bool bch_bucket_add_unused(struct cache *, struct bucket *);
 
-long bch_bucket_alloc(struct cache *, unsigned, struct closure *);
+long bch_bucket_alloc(struct cache *, unsigned, bool);
 void bch_bucket_free(struct cache_set *, struct bkey *);
 
 int __bch_bucket_alloc_set(struct cache_set *, unsigned,
-			   struct bkey *, int, struct closure *);
+			   struct bkey *, int, bool);
 int bch_bucket_alloc_set(struct cache_set *, unsigned,
-			 struct bkey *, int, struct closure *);
+			 struct bkey *, int, bool);
+bool bch_alloc_sectors(struct cache_set *, struct bkey *, unsigned,
+		       unsigned, unsigned, bool);
 
 __printf(2, 3)
 bool bch_cache_set_error(struct cache_set *, const char *, ...);
@@ -1187,7 +927,7 @@ bool bch_cache_set_error(struct cache_set *, const char *, ...);
 void bch_prio_write(struct cache *);
 void bch_write_bdev_super(struct cached_dev *, struct closure *);
 
-extern struct workqueue_struct *bcache_wq, *bch_gc_wq;
+extern struct workqueue_struct *bcache_wq;
 extern const char * const bch_cache_modes[];
 extern struct mutex bch_register_lock;
 extern struct list_head bch_cache_sets;
@@ -1220,15 +960,14 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *);
 void bch_btree_cache_free(struct cache_set *);
 int bch_btree_cache_alloc(struct cache_set *);
 void bch_moving_init_cache_set(struct cache_set *);
+int bch_open_buckets_alloc(struct cache_set *);
+void bch_open_buckets_free(struct cache_set *);
 
 int bch_cache_allocator_start(struct cache *ca);
-void bch_cache_allocator_exit(struct cache *ca);
 int bch_cache_allocator_init(struct cache *ca);
 
 void bch_debug_exit(void);
 int bch_debug_init(struct kobject *);
-void bch_writeback_exit(void);
-int bch_writeback_init(void);
 void bch_request_exit(void);
 int bch_request_init(void);
 void bch_btree_exit(void);
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c
index 22d1ae72c282..7d388b8bb50e 100644
--- a/drivers/md/bcache/bset.c
+++ b/drivers/md/bcache/bset.c
@@ -14,22 +14,12 @@
 
 /* Keylists */
 
-void bch_keylist_copy(struct keylist *dest, struct keylist *src)
-{
-	*dest = *src;
-
-	if (src->list == src->d) {
-		size_t n = (uint64_t *) src->top - src->d;
-		dest->top = (struct bkey *) &dest->d[n];
-		dest->list = dest->d;
-	}
-}
-
 int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
 {
-	unsigned oldsize = (uint64_t *) l->top - l->list;
-	unsigned newsize = oldsize + 2 + nptrs;
-	uint64_t *new;
+	size_t oldsize = bch_keylist_nkeys(l);
+	size_t newsize = oldsize + 2 + nptrs;
+	uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p;
+	uint64_t *new_keys;
 
 	/* The journalling code doesn't handle the case where the keys to insert
 	 * is bigger than an empty write: If we just return -ENOMEM here,
@@ -45,24 +35,23 @@ int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
 	    roundup_pow_of_two(oldsize) == newsize)
 		return 0;
 
-	new = krealloc(l->list == l->d ? NULL : l->list,
-		       sizeof(uint64_t) * newsize, GFP_NOIO);
+	new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO);
 
-	if (!new)
+	if (!new_keys)
 		return -ENOMEM;
 
-	if (l->list == l->d)
-		memcpy(new, l->list, sizeof(uint64_t) * KEYLIST_INLINE);
+	if (!old_keys)
+		memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize);
 
-	l->list = new;
-	l->top = (struct bkey *) (&l->list[oldsize]);
+	l->keys_p = new_keys;
+	l->top_p = new_keys + oldsize;
 
 	return 0;
 }
 
 struct bkey *bch_keylist_pop(struct keylist *l)
 {
-	struct bkey *k = l->bottom;
+	struct bkey *k = l->keys;
 
 	if (k == l->top)
 		return NULL;
@@ -73,21 +62,20 @@ struct bkey *bch_keylist_pop(struct keylist *l)
 	return l->top = k;
 }
 
-/* Pointer validation */
-
-bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k)
+void bch_keylist_pop_front(struct keylist *l)
 {
-	unsigned i;
-	char buf[80];
+	l->top_p -= bkey_u64s(l->keys);
 
-	if (level && (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k)))
-		goto bad;
+	memmove(l->keys,
+		bkey_next(l->keys),
+		bch_keylist_bytes(l));
+}
 
-	if (!level && KEY_SIZE(k) > KEY_OFFSET(k))
-		goto bad;
+/* Pointer validation */
 
-	if (!KEY_SIZE(k))
-		return true;
+static bool __ptr_invalid(struct cache_set *c, const struct bkey *k)
+{
+	unsigned i;
 
 	for (i = 0; i < KEY_PTRS(k); i++)
 		if (ptr_available(c, k, i)) {
@@ -98,13 +86,83 @@ bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k)
 			if (KEY_SIZE(k) + r > c->sb.bucket_size ||
 			    bucket <  ca->sb.first_bucket ||
 			    bucket >= ca->sb.nbuckets)
-				goto bad;
+				return true;
 		}
 
 	return false;
+}
+
+bool bch_btree_ptr_invalid(struct cache_set *c, const struct bkey *k)
+{
+	char buf[80];
+
+	if (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k))
+		goto bad;
+
+	if (__ptr_invalid(c, k))
+		goto bad;
+
+	return false;
+bad:
+	bch_bkey_to_text(buf, sizeof(buf), k);
+	cache_bug(c, "spotted btree ptr %s: %s", buf, bch_ptr_status(c, k));
+	return true;
+}
+
+bool bch_extent_ptr_invalid(struct cache_set *c, const struct bkey *k)
+{
+	char buf[80];
+
+	if (!KEY_SIZE(k))
+		return true;
+
+	if (KEY_SIZE(k) > KEY_OFFSET(k))
+		goto bad;
+
+	if (__ptr_invalid(c, k))
+		goto bad;
+
+	return false;
 bad:
 	bch_bkey_to_text(buf, sizeof(buf), k);
-	cache_bug(c, "spotted bad key %s: %s", buf, bch_ptr_status(c, k));
+	cache_bug(c, "spotted extent %s: %s", buf, bch_ptr_status(c, k));
+	return true;
+}
+
+static bool ptr_bad_expensive_checks(struct btree *b, const struct bkey *k,
+				     unsigned ptr)
+{
+	struct bucket *g = PTR_BUCKET(b->c, k, ptr);
+	char buf[80];
+
+	if (mutex_trylock(&b->c->bucket_lock)) {
+		if (b->level) {
+			if (KEY_DIRTY(k) ||
+			    g->prio != BTREE_PRIO ||
+			    (b->c->gc_mark_valid &&
+			     GC_MARK(g) != GC_MARK_METADATA))
+				goto err;
+
+		} else {
+			if (g->prio == BTREE_PRIO)
+				goto err;
+
+			if (KEY_DIRTY(k) &&
+			    b->c->gc_mark_valid &&
+			    GC_MARK(g) != GC_MARK_DIRTY)
+				goto err;
+		}
+		mutex_unlock(&b->c->bucket_lock);
+	}
+
+	return false;
+err:
+	mutex_unlock(&b->c->bucket_lock);
+	bch_bkey_to_text(buf, sizeof(buf), k);
+	btree_bug(b,
+"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
+		  buf, PTR_BUCKET_NR(b->c, k, ptr), atomic_read(&g->pin),
+		  g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
 	return true;
 }
 
@@ -118,64 +176,29 @@ bool bch_ptr_bad(struct btree *b, const struct bkey *k)
 	    bch_ptr_invalid(b, k))
 		return true;
 
-	if (KEY_PTRS(k) && PTR_DEV(k, 0) == PTR_CHECK_DEV)
-		return true;
+	for (i = 0; i < KEY_PTRS(k); i++) {
+		if (!ptr_available(b->c, k, i))
+			return true;
 
-	for (i = 0; i < KEY_PTRS(k); i++)
-		if (ptr_available(b->c, k, i)) {
-			g = PTR_BUCKET(b->c, k, i);
-			stale = ptr_stale(b->c, k, i);
+		g = PTR_BUCKET(b->c, k, i);
+		stale = ptr_stale(b->c, k, i);
 
-			btree_bug_on(stale > 96, b,
-				     "key too stale: %i, need_gc %u",
-				     stale, b->c->need_gc);
+		btree_bug_on(stale > 96, b,
+			     "key too stale: %i, need_gc %u",
+			     stale, b->c->need_gc);
 
-			btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
-				     b, "stale dirty pointer");
+		btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
+			     b, "stale dirty pointer");
 
-			if (stale)
-				return true;
+		if (stale)
+			return true;
 
-#ifdef CONFIG_BCACHE_EDEBUG
-			if (!mutex_trylock(&b->c->bucket_lock))
-				continue;
-
-			if (b->level) {
-				if (KEY_DIRTY(k) ||
-				    g->prio != BTREE_PRIO ||
-				    (b->c->gc_mark_valid &&
-				     GC_MARK(g) != GC_MARK_METADATA))
-					goto bug;
-
-			} else {
-				if (g->prio == BTREE_PRIO)
-					goto bug;
-
-				if (KEY_DIRTY(k) &&
-				    b->c->gc_mark_valid &&
-				    GC_MARK(g) != GC_MARK_DIRTY)
-					goto bug;
-			}
-			mutex_unlock(&b->c->bucket_lock);
-#endif
-		}
+		if (expensive_debug_checks(b->c) &&
+		    ptr_bad_expensive_checks(b, k, i))
+			return true;
+	}
 
 	return false;
-#ifdef CONFIG_BCACHE_EDEBUG
-bug:
-	mutex_unlock(&b->c->bucket_lock);
-
-	{
-		char buf[80];
-
-		bch_bkey_to_text(buf, sizeof(buf), k);
-		btree_bug(b,
-"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
-			  buf, PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
-			  g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
-	}
-	return true;
-#endif
 }
 
 /* Key/pointer manipulation */
@@ -458,16 +481,8 @@ static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
 
 static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
 {
-#ifdef CONFIG_X86_64
-	asm("shrd %[shift],%[high],%[low]"
-	    : [low] "+Rm" (low)
-	    : [high] "R" (high),
-	    [shift] "ci" (shift)
-	    : "cc");
-#else
 	low >>= shift;
 	low  |= (high << 1) << (63U - shift);
-#endif
 	return low;
 }
 
@@ -686,7 +701,7 @@ void bch_bset_init_next(struct btree *b)
 	} else
 		get_random_bytes(&i->seq, sizeof(uint64_t));
 
-	i->magic	= bset_magic(b->c);
+	i->magic	= bset_magic(&b->c->sb);
 	i->version	= 0;
 	i->keys		= 0;
 
@@ -824,16 +839,16 @@ struct bkey *__bch_bset_search(struct btree *b, struct bset_tree *t,
 	} else
 		i = bset_search_write_set(b, t, search);
 
-#ifdef CONFIG_BCACHE_EDEBUG
-	BUG_ON(bset_written(b, t) &&
-	       i.l != t->data->start &&
-	       bkey_cmp(tree_to_prev_bkey(t,
-		  inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
-			search) > 0);
+	if (expensive_debug_checks(b->c)) {
+		BUG_ON(bset_written(b, t) &&
+		       i.l != t->data->start &&
+		       bkey_cmp(tree_to_prev_bkey(t,
+			  inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
+				search) > 0);
 
-	BUG_ON(i.r != end(t->data) &&
-	       bkey_cmp(i.r, search) <= 0);
-#endif
+		BUG_ON(i.r != end(t->data) &&
+		       bkey_cmp(i.r, search) <= 0);
+	}
 
 	while (likely(i.l != i.r) &&
 	       bkey_cmp(i.l, search) <= 0)
@@ -844,6 +859,13 @@ struct bkey *__bch_bset_search(struct btree *b, struct bset_tree *t,
 
 /* Btree iterator */
 
+/*
+ * Returns true if l > r - unless l == r, in which case returns true if l is
+ * older than r.
+ *
+ * Necessary for btree_sort_fixup() - if there are multiple keys that compare
+ * equal in different sets, we have to process them newest to oldest.
+ */
 static inline bool btree_iter_cmp(struct btree_iter_set l,
 				  struct btree_iter_set r)
 {
@@ -867,12 +889,16 @@ void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
 }
 
 struct bkey *__bch_btree_iter_init(struct btree *b, struct btree_iter *iter,
-			       struct bkey *search, struct bset_tree *start)
+				   struct bkey *search, struct bset_tree *start)
 {
 	struct bkey *ret = NULL;
 	iter->size = ARRAY_SIZE(iter->data);
 	iter->used = 0;
 
+#ifdef CONFIG_BCACHE_DEBUG
+	iter->b = b;
+#endif
+
 	for (; start <= &b->sets[b->nsets]; start++) {
 		ret = bch_bset_search(b, start, search);
 		bch_btree_iter_push(iter, ret, end(start->data));
@@ -887,6 +913,8 @@ struct bkey *bch_btree_iter_next(struct btree_iter *iter)
 	struct bkey *ret = NULL;
 
 	if (!btree_iter_end(iter)) {
+		bch_btree_iter_next_check(iter);
+
 		ret = iter->data->k;
 		iter->data->k = bkey_next(iter->data->k);
 
@@ -916,14 +944,6 @@ struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
 	return ret;
 }
 
-struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
-{
-	struct btree_iter iter;
-
-	bch_btree_iter_init(b, &iter, search);
-	return bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
-}
-
 /* Mergesort */
 
 static void sort_key_next(struct btree_iter *iter,
@@ -998,7 +1018,6 @@ static void btree_mergesort(struct btree *b, struct bset *out,
 	out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
 
 	pr_debug("sorted %i keys", out->keys);
-	bch_check_key_order(b, out);
 }
 
 static void __btree_sort(struct btree *b, struct btree_iter *iter,
@@ -1029,7 +1048,7 @@ static void __btree_sort(struct btree *b, struct btree_iter *iter,
 		 * memcpy()
 		 */
 
-		out->magic	= bset_magic(b->c);
+		out->magic	= bset_magic(&b->c->sb);
 		out->seq	= b->sets[0].data->seq;
 		out->version	= b->sets[0].data->version;
 		swap(out, b->sets[0].data);
@@ -1050,24 +1069,21 @@ static void __btree_sort(struct btree *b, struct btree_iter *iter,
 	if (b->written)
 		bset_build_written_tree(b);
 
-	if (!start) {
-		spin_lock(&b->c->sort_time_lock);
+	if (!start)
 		bch_time_stats_update(&b->c->sort_time, start_time);
-		spin_unlock(&b->c->sort_time_lock);
-	}
 }
 
 void bch_btree_sort_partial(struct btree *b, unsigned start)
 {
-	size_t oldsize = 0, order = b->page_order, keys = 0;
+	size_t order = b->page_order, keys = 0;
 	struct btree_iter iter;
+	int oldsize = bch_count_data(b);
+
 	__bch_btree_iter_init(b, &iter, NULL, &b->sets[start]);
 
 	BUG_ON(b->sets[b->nsets].data == write_block(b) &&
 	       (b->sets[b->nsets].size || b->nsets));
 
-	if (b->written)
-		oldsize = bch_count_data(b);
 
 	if (start) {
 		unsigned i;
@@ -1083,7 +1099,7 @@ void bch_btree_sort_partial(struct btree *b, unsigned start)
 
 	__btree_sort(b, &iter, start, order, false);
 
-	EBUG_ON(b->written && bch_count_data(b) != oldsize);
+	EBUG_ON(b->written && oldsize >= 0 && bch_count_data(b) != oldsize);
 }
 
 void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
@@ -1101,9 +1117,7 @@ void bch_btree_sort_into(struct btree *b, struct btree *new)
 
 	btree_mergesort(b, new->sets->data, &iter, false, true);
 
-	spin_lock(&b->c->sort_time_lock);
 	bch_time_stats_update(&b->c->sort_time, start_time);
-	spin_unlock(&b->c->sort_time_lock);
 
 	bkey_copy_key(&new->key, &b->key);
 	new->sets->size = 0;
@@ -1148,16 +1162,16 @@ out:
 /* Sysfs stuff */
 
 struct bset_stats {
+	struct btree_op op;
 	size_t nodes;
 	size_t sets_written, sets_unwritten;
 	size_t bytes_written, bytes_unwritten;
 	size_t floats, failed;
 };
 
-static int bch_btree_bset_stats(struct btree *b, struct btree_op *op,
-			    struct bset_stats *stats)
+static int btree_bset_stats(struct btree_op *op, struct btree *b)
 {
-	struct bkey *k;
+	struct bset_stats *stats = container_of(op, struct bset_stats, op);
 	unsigned i;
 
 	stats->nodes++;
@@ -1182,30 +1196,19 @@ static int bch_btree_bset_stats(struct btree *b, struct btree_op *op,
 		}
 	}
 
-	if (b->level) {
-		struct btree_iter iter;
-
-		for_each_key_filter(b, k, &iter, bch_ptr_bad) {
-			int ret = btree(bset_stats, k, b, op, stats);
-			if (ret)
-				return ret;
-		}
-	}
-
-	return 0;
+	return MAP_CONTINUE;
 }
 
 int bch_bset_print_stats(struct cache_set *c, char *buf)
 {
-	struct btree_op op;
 	struct bset_stats t;
 	int ret;
 
-	bch_btree_op_init_stack(&op);
 	memset(&t, 0, sizeof(struct bset_stats));
+	bch_btree_op_init(&t.op, -1);
 
-	ret = btree_root(bset_stats, c, &op, &t);
-	if (ret)
+	ret = bch_btree_map_nodes(&t.op, c, &ZERO_KEY, btree_bset_stats);
+	if (ret < 0)
 		return ret;
 
 	return snprintf(buf, PAGE_SIZE,
diff --git a/drivers/md/bcache/bset.h b/drivers/md/bcache/bset.h
index ae115a253d73..1d3c24f9fa0e 100644
--- a/drivers/md/bcache/bset.h
+++ b/drivers/md/bcache/bset.h
@@ -148,6 +148,9 @@
 
 struct btree_iter {
 	size_t size, used;
+#ifdef CONFIG_BCACHE_DEBUG
+	struct btree *b;
+#endif
 	struct btree_iter_set {
 		struct bkey *k, *end;
 	} data[MAX_BSETS];
@@ -193,54 +196,26 @@ static __always_inline int64_t bkey_cmp(const struct bkey *l,
 		: (int64_t) KEY_OFFSET(l) - (int64_t) KEY_OFFSET(r);
 }
 
-static inline size_t bkey_u64s(const struct bkey *k)
-{
-	BUG_ON(KEY_CSUM(k) > 1);
-	return 2 + KEY_PTRS(k) + (KEY_CSUM(k) ? 1 : 0);
-}
-
-static inline size_t bkey_bytes(const struct bkey *k)
-{
-	return bkey_u64s(k) * sizeof(uint64_t);
-}
-
-static inline void bkey_copy(struct bkey *dest, const struct bkey *src)
-{
-	memcpy(dest, src, bkey_bytes(src));
-}
-
-static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
-{
-	if (!src)
-		src = &KEY(0, 0, 0);
-
-	SET_KEY_INODE(dest, KEY_INODE(src));
-	SET_KEY_OFFSET(dest, KEY_OFFSET(src));
-}
-
-static inline struct bkey *bkey_next(const struct bkey *k)
-{
-	uint64_t *d = (void *) k;
-	return (struct bkey *) (d + bkey_u64s(k));
-}
-
 /* Keylists */
 
 struct keylist {
-	struct bkey		*top;
 	union {
-		uint64_t		*list;
-		struct bkey		*bottom;
+		struct bkey		*keys;
+		uint64_t		*keys_p;
+	};
+	union {
+		struct bkey		*top;
+		uint64_t		*top_p;
 	};
 
 	/* Enough room for btree_split's keys without realloc */
 #define KEYLIST_INLINE		16
-	uint64_t		d[KEYLIST_INLINE];
+	uint64_t		inline_keys[KEYLIST_INLINE];
 };
 
 static inline void bch_keylist_init(struct keylist *l)
 {
-	l->top = (void *) (l->list = l->d);
+	l->top_p = l->keys_p = l->inline_keys;
 }
 
 static inline void bch_keylist_push(struct keylist *l)
@@ -256,17 +231,32 @@ static inline void bch_keylist_add(struct keylist *l, struct bkey *k)
 
 static inline bool bch_keylist_empty(struct keylist *l)
 {
-	return l->top == (void *) l->list;
+	return l->top == l->keys;
+}
+
+static inline void bch_keylist_reset(struct keylist *l)
+{
+	l->top = l->keys;
 }
 
 static inline void bch_keylist_free(struct keylist *l)
 {
-	if (l->list != l->d)
-		kfree(l->list);
+	if (l->keys_p != l->inline_keys)
+		kfree(l->keys_p);
+}
+
+static inline size_t bch_keylist_nkeys(struct keylist *l)
+{
+	return l->top_p - l->keys_p;
+}
+
+static inline size_t bch_keylist_bytes(struct keylist *l)
+{
+	return bch_keylist_nkeys(l) * sizeof(uint64_t);
 }
 
-void bch_keylist_copy(struct keylist *, struct keylist *);
 struct bkey *bch_keylist_pop(struct keylist *);
+void bch_keylist_pop_front(struct keylist *);
 int bch_keylist_realloc(struct keylist *, int, struct cache_set *);
 
 void bch_bkey_copy_single_ptr(struct bkey *, const struct bkey *,
@@ -287,7 +277,9 @@ static inline bool bch_cut_back(const struct bkey *where, struct bkey *k)
 }
 
 const char *bch_ptr_status(struct cache_set *, const struct bkey *);
-bool __bch_ptr_invalid(struct cache_set *, int level, const struct bkey *);
+bool bch_btree_ptr_invalid(struct cache_set *, const struct bkey *);
+bool bch_extent_ptr_invalid(struct cache_set *, const struct bkey *);
+
 bool bch_ptr_bad(struct btree *, const struct bkey *);
 
 static inline uint8_t gen_after(uint8_t a, uint8_t b)
@@ -311,7 +303,6 @@ static inline bool ptr_available(struct cache_set *c, const struct bkey *k,
 
 typedef bool (*ptr_filter_fn)(struct btree *, const struct bkey *);
 
-struct bkey *bch_next_recurse_key(struct btree *, struct bkey *);
 struct bkey *bch_btree_iter_next(struct btree_iter *);
 struct bkey *bch_btree_iter_next_filter(struct btree_iter *,
 					struct btree *, ptr_filter_fn);
@@ -361,12 +352,30 @@ void bch_bset_fix_lookup_table(struct btree *, struct bkey *);
 struct bkey *__bch_bset_search(struct btree *, struct bset_tree *,
 			   const struct bkey *);
 
+/*
+ * Returns the first key that is strictly greater than search
+ */
 static inline struct bkey *bch_bset_search(struct btree *b, struct bset_tree *t,
 					   const struct bkey *search)
 {
 	return search ? __bch_bset_search(b, t, search) : t->data->start;
 }
 
+#define PRECEDING_KEY(_k)					\
+({								\
+	struct bkey *_ret = NULL;				\
+								\
+	if (KEY_INODE(_k) || KEY_OFFSET(_k)) {			\
+		_ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0);	\
+								\
+		if (!_ret->low)					\
+			_ret->high--;				\
+		_ret->low--;					\
+	}							\
+								\
+	_ret;							\
+})
+
 bool bch_bkey_try_merge(struct btree *, struct bkey *, struct bkey *);
 void bch_btree_sort_lazy(struct btree *);
 void bch_btree_sort_into(struct btree *, struct btree *);
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index f42fc7ed9cd6..5e2765aadce1 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -23,12 +23,13 @@
 #include "bcache.h"
 #include "btree.h"
 #include "debug.h"
-#include "request.h"
 #include "writeback.h"
 
 #include <linux/slab.h>
 #include <linux/bitops.h>
+#include <linux/freezer.h>
 #include <linux/hash.h>
+#include <linux/kthread.h>
 #include <linux/prefetch.h>
 #include <linux/random.h>
 #include <linux/rcupdate.h>
@@ -88,15 +89,13 @@
  * Test module load/unload
  */
 
-static const char * const op_types[] = {
-	"insert", "replace"
+enum {
+	BTREE_INSERT_STATUS_INSERT,
+	BTREE_INSERT_STATUS_BACK_MERGE,
+	BTREE_INSERT_STATUS_OVERWROTE,
+	BTREE_INSERT_STATUS_FRONT_MERGE,
 };
 
-static const char *op_type(struct btree_op *op)
-{
-	return op_types[op->type];
-}
-
 #define MAX_NEED_GC		64
 #define MAX_SAVE_PRIO		72
 
@@ -105,23 +104,89 @@ static const char *op_type(struct btree_op *op)
 #define PTR_HASH(c, k)							\
 	(((k)->ptr[0] >> c->bucket_bits) | PTR_GEN(k, 0))
 
-struct workqueue_struct *bch_gc_wq;
 static struct workqueue_struct *btree_io_wq;
 
-void bch_btree_op_init_stack(struct btree_op *op)
+static inline bool should_split(struct btree *b)
 {
-	memset(op, 0, sizeof(struct btree_op));
-	closure_init_stack(&op->cl);
-	op->lock = -1;
-	bch_keylist_init(&op->keys);
+	struct bset *i = write_block(b);
+	return b->written >= btree_blocks(b) ||
+		(b->written + __set_blocks(i, i->keys + 15, b->c)
+		 > btree_blocks(b));
 }
 
+#define insert_lock(s, b)	((b)->level <= (s)->lock)
+
+/*
+ * These macros are for recursing down the btree - they handle the details of
+ * locking and looking up nodes in the cache for you. They're best treated as
+ * mere syntax when reading code that uses them.
+ *
+ * op->lock determines whether we take a read or a write lock at a given depth.
+ * If you've got a read lock and find that you need a write lock (i.e. you're
+ * going to have to split), set op->lock and return -EINTR; btree_root() will
+ * call you again and you'll have the correct lock.
+ */
+
+/**
+ * btree - recurse down the btree on a specified key
+ * @fn:		function to call, which will be passed the child node
+ * @key:	key to recurse on
+ * @b:		parent btree node
+ * @op:		pointer to struct btree_op
+ */
+#define btree(fn, key, b, op, ...)					\
+({									\
+	int _r, l = (b)->level - 1;					\
+	bool _w = l <= (op)->lock;					\
+	struct btree *_child = bch_btree_node_get((b)->c, key, l, _w);	\
+	if (!IS_ERR(_child)) {						\
+		_child->parent = (b);					\
+		_r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__);	\
+		rw_unlock(_w, _child);					\
+	} else								\
+		_r = PTR_ERR(_child);					\
+	_r;								\
+})
+
+/**
+ * btree_root - call a function on the root of the btree
+ * @fn:		function to call, which will be passed the child node
+ * @c:		cache set
+ * @op:		pointer to struct btree_op
+ */
+#define btree_root(fn, c, op, ...)					\
+({									\
+	int _r = -EINTR;						\
+	do {								\
+		struct btree *_b = (c)->root;				\
+		bool _w = insert_lock(op, _b);				\
+		rw_lock(_w, _b, _b->level);				\
+		if (_b == (c)->root &&					\
+		    _w == insert_lock(op, _b)) {			\
+			_b->parent = NULL;				\
+			_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__);	\
+		}							\
+		rw_unlock(_w, _b);					\
+		bch_cannibalize_unlock(c);				\
+		if (_r == -ENOSPC) {					\
+			wait_event((c)->try_wait,			\
+				   !(c)->try_harder);			\
+			_r = -EINTR;					\
+		}							\
+	} while (_r == -EINTR);						\
+									\
+	_r;								\
+})
+
 /* Btree key manipulation */
 
-static void bkey_put(struct cache_set *c, struct bkey *k, int level)
+void bkey_put(struct cache_set *c, struct bkey *k)
 {
-	if ((level && KEY_OFFSET(k)) || !level)
-		__bkey_put(c, k);
+	unsigned i;
+
+	for (i = 0; i < KEY_PTRS(k); i++)
+		if (ptr_available(c, k, i))
+			atomic_dec_bug(&PTR_BUCKET(c, k, i)->pin);
 }
 
 /* Btree IO */
@@ -145,6 +210,10 @@ static void bch_btree_node_read_done(struct btree *b)
 	iter->size = b->c->sb.bucket_size / b->c->sb.block_size;
 	iter->used = 0;
 
+#ifdef CONFIG_BCACHE_DEBUG
+	iter->b = b;
+#endif
+
 	if (!i->seq)
 		goto err;
 
@@ -160,7 +229,7 @@ static void bch_btree_node_read_done(struct btree *b)
 			goto err;
 
 		err = "bad magic";
-		if (i->magic != bset_magic(b->c))
+		if (i->magic != bset_magic(&b->c->sb))
 			goto err;
 
 		err = "bad checksum";
@@ -248,10 +317,7 @@ void bch_btree_node_read(struct btree *b)
 		goto err;
 
 	bch_btree_node_read_done(b);
-
-	spin_lock(&b->c->btree_read_time_lock);
 	bch_time_stats_update(&b->c->btree_read_time, start_time);
-	spin_unlock(&b->c->btree_read_time_lock);
 
 	return;
 err:
@@ -327,7 +393,7 @@ static void do_btree_node_write(struct btree *b)
 	b->bio = bch_bbio_alloc(b->c);
 
 	b->bio->bi_end_io	= btree_node_write_endio;
-	b->bio->bi_private	= &b->io.cl;
+	b->bio->bi_private	= cl;
 	b->bio->bi_rw		= REQ_META|WRITE_SYNC|REQ_FUA;
 	b->bio->bi_size		= set_blocks(i, b->c) * block_bytes(b->c);
 	bch_bio_map(b->bio, i);
@@ -383,7 +449,7 @@ void bch_btree_node_write(struct btree *b, struct closure *parent)
 	BUG_ON(b->written >= btree_blocks(b));
 	BUG_ON(b->written && !i->keys);
 	BUG_ON(b->sets->data->seq != i->seq);
-	bch_check_key_order(b, i);
+	bch_check_keys(b, "writing");
 
 	cancel_delayed_work(&b->work);
 
@@ -405,6 +471,15 @@ void bch_btree_node_write(struct btree *b, struct closure *parent)
 		bch_bset_init_next(b);
 }
 
+static void bch_btree_node_write_sync(struct btree *b)
+{
+	struct closure cl;
+
+	closure_init_stack(&cl);
+	bch_btree_node_write(b, &cl);
+	closure_sync(&cl);
+}
+
 static void btree_node_write_work(struct work_struct *w)
 {
 	struct btree *b = container_of(to_delayed_work(w), struct btree, work);
@@ -416,7 +491,7 @@ static void btree_node_write_work(struct work_struct *w)
 	rw_unlock(true, b);
 }
 
-static void bch_btree_leaf_dirty(struct btree *b, struct btree_op *op)
+static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
 {
 	struct bset *i = b->sets[b->nsets].data;
 	struct btree_write *w = btree_current_write(b);
@@ -429,15 +504,15 @@ static void bch_btree_leaf_dirty(struct btree *b, struct btree_op *op)
 
 	set_btree_node_dirty(b);
 
-	if (op && op->journal) {
+	if (journal_ref) {
 		if (w->journal &&
-		    journal_pin_cmp(b->c, w, op)) {
+		    journal_pin_cmp(b->c, w->journal, journal_ref)) {
 			atomic_dec_bug(w->journal);
 			w->journal = NULL;
 		}
 
 		if (!w->journal) {
-			w->journal = op->journal;
+			w->journal = journal_ref;
 			atomic_inc(w->journal);
 		}
 	}
@@ -566,33 +641,32 @@ static struct btree *mca_bucket_alloc(struct cache_set *c,
 	return b;
 }
 
-static int mca_reap(struct btree *b, struct closure *cl, unsigned min_order)
+static int mca_reap(struct btree *b, unsigned min_order, bool flush)
 {
+	struct closure cl;
+
+	closure_init_stack(&cl);
 	lockdep_assert_held(&b->c->bucket_lock);
 
 	if (!down_write_trylock(&b->lock))
 		return -ENOMEM;
 
-	if (b->page_order < min_order) {
+	BUG_ON(btree_node_dirty(b) && !b->sets[0].data);
+
+	if (b->page_order < min_order ||
+	    (!flush &&
+	     (btree_node_dirty(b) ||
+	      atomic_read(&b->io.cl.remaining) != -1))) {
 		rw_unlock(true, b);
 		return -ENOMEM;
 	}
 
-	BUG_ON(btree_node_dirty(b) && !b->sets[0].data);
-
-	if (cl && btree_node_dirty(b))
-		bch_btree_node_write(b, NULL);
-
-	if (cl)
-		closure_wait_event_async(&b->io.wait, cl,
-			 atomic_read(&b->io.cl.remaining) == -1);
+	if (btree_node_dirty(b))
+		bch_btree_node_write_sync(b);
 
-	if (btree_node_dirty(b) ||
-	    !closure_is_unlocked(&b->io.cl) ||
-	    work_pending(&b->work.work)) {
-		rw_unlock(true, b);
-		return -EAGAIN;
-	}
+	/* wait for any in flight btree write */
+	closure_wait_event(&b->io.wait, &cl,
+			   atomic_read(&b->io.cl.remaining) == -1);
 
 	return 0;
 }
@@ -633,7 +707,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
 			break;
 
 		if (++i > 3 &&
-		    !mca_reap(b, NULL, 0)) {
+		    !mca_reap(b, 0, false)) {
 			mca_data_free(b);
 			rw_unlock(true, b);
 			freed++;
@@ -652,7 +726,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
 		list_rotate_left(&c->btree_cache);
 
 		if (!b->accessed &&
-		    !mca_reap(b, NULL, 0)) {
+		    !mca_reap(b, 0, false)) {
 			mca_bucket_free(b);
 			mca_data_free(b);
 			rw_unlock(true, b);
@@ -723,12 +797,9 @@ int bch_btree_cache_alloc(struct cache_set *c)
 {
 	unsigned i;
 
-	/* XXX: doesn't check for errors */
-
-	closure_init_unlocked(&c->gc);
-
 	for (i = 0; i < mca_reserve(c); i++)
-		mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL);
+		if (!mca_bucket_alloc(c, &ZERO_KEY, GFP_KERNEL))
+			return -ENOMEM;
 
 	list_splice_init(&c->btree_cache,
 			 &c->btree_cache_freeable);
@@ -775,52 +846,27 @@ out:
 	return b;
 }
 
-static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k,
-				     int level, struct closure *cl)
+static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k)
 {
-	int ret = -ENOMEM;
-	struct btree *i;
+	struct btree *b;
 
 	trace_bcache_btree_cache_cannibalize(c);
 
-	if (!cl)
-		return ERR_PTR(-ENOMEM);
-
-	/*
-	 * Trying to free up some memory - i.e. reuse some btree nodes - may
-	 * require initiating IO to flush the dirty part of the node. If we're
-	 * running under generic_make_request(), that IO will never finish and
-	 * we would deadlock. Returning -EAGAIN causes the cache lookup code to
-	 * punt to workqueue and retry.
-	 */
-	if (current->bio_list)
-		return ERR_PTR(-EAGAIN);
-
-	if (c->try_harder && c->try_harder != cl) {
-		closure_wait_event_async(&c->try_wait, cl, !c->try_harder);
-		return ERR_PTR(-EAGAIN);
-	}
+	if (!c->try_harder) {
+		c->try_harder = current;
+		c->try_harder_start = local_clock();
+	} else if (c->try_harder != current)
+		return ERR_PTR(-ENOSPC);
 
-	c->try_harder = cl;
-	c->try_harder_start = local_clock();
-retry:
-	list_for_each_entry_reverse(i, &c->btree_cache, list) {
-		int r = mca_reap(i, cl, btree_order(k));
-		if (!r)
-			return i;
-		if (r != -ENOMEM)
-			ret = r;
-	}
+	list_for_each_entry_reverse(b, &c->btree_cache, list)
+		if (!mca_reap(b, btree_order(k), false))
+			return b;
 
-	if (ret == -EAGAIN &&
-	    closure_blocking(cl)) {
-		mutex_unlock(&c->bucket_lock);
-		closure_sync(cl);
-		mutex_lock(&c->bucket_lock);
-		goto retry;
-	}
+	list_for_each_entry_reverse(b, &c->btree_cache, list)
+		if (!mca_reap(b, btree_order(k), true))
+			return b;
 
-	return ERR_PTR(ret);
+	return ERR_PTR(-ENOMEM);
 }
 
 /*
@@ -829,20 +875,21 @@ retry:
  * cannibalize_bucket() will take. This means every time we unlock the root of
  * the btree, we need to release this lock if we have it held.
  */
-void bch_cannibalize_unlock(struct cache_set *c, struct closure *cl)
+static void bch_cannibalize_unlock(struct cache_set *c)
 {
-	if (c->try_harder == cl) {
+	if (c->try_harder == current) {
 		bch_time_stats_update(&c->try_harder_time, c->try_harder_start);
 		c->try_harder = NULL;
-		__closure_wake_up(&c->try_wait);
+		wake_up(&c->try_wait);
 	}
 }
 
-static struct btree *mca_alloc(struct cache_set *c, struct bkey *k,
-			       int level, struct closure *cl)
+static struct btree *mca_alloc(struct cache_set *c, struct bkey *k, int level)
 {
 	struct btree *b;
 
+	BUG_ON(current->bio_list);
+
 	lockdep_assert_held(&c->bucket_lock);
 
 	if (mca_find(c, k))
@@ -852,14 +899,14 @@ static struct btree *mca_alloc(struct cache_set *c, struct bkey *k,
 	 * the list. Check if there's any freed nodes there:
 	 */
 	list_for_each_entry(b, &c->btree_cache_freeable, list)
-		if (!mca_reap(b, NULL, btree_order(k)))
+		if (!mca_reap(b, btree_order(k), false))
 			goto out;
 
 	/* We never free struct btree itself, just the memory that holds the on
 	 * disk node. Check the freed list before allocating a new one:
 	 */
 	list_for_each_entry(b, &c->btree_cache_freed, list)
-		if (!mca_reap(b, NULL, 0)) {
+		if (!mca_reap(b, 0, false)) {
 			mca_data_alloc(b, k, __GFP_NOWARN|GFP_NOIO);
 			if (!b->sets[0].data)
 				goto err;
@@ -884,6 +931,7 @@ out:
 
 	lock_set_subclass(&b->lock.dep_map, level + 1, _THIS_IP_);
 	b->level	= level;
+	b->parent	= (void *) ~0UL;
 
 	mca_reinit(b);
 
@@ -892,7 +940,7 @@ err:
 	if (b)
 		rw_unlock(true, b);
 
-	b = mca_cannibalize(c, k, level, cl);
+	b = mca_cannibalize(c, k);
 	if (!IS_ERR(b))
 		goto out;
 
@@ -903,17 +951,15 @@ err:
  * bch_btree_node_get - find a btree node in the cache and lock it, reading it
  * in from disk if necessary.
  *
- * If IO is necessary, it uses the closure embedded in struct btree_op to wait;
- * if that closure is in non blocking mode, will return -EAGAIN.
+ * If IO is necessary and running under generic_make_request, returns -EAGAIN.
  *
  * The btree node will have either a read or a write lock held, depending on
  * level and op->lock.
  */
 struct btree *bch_btree_node_get(struct cache_set *c, struct bkey *k,
-				 int level, struct btree_op *op)
+				 int level, bool write)
 {
 	int i = 0;
-	bool write = level <= op->lock;
 	struct btree *b;
 
 	BUG_ON(level < 0);
@@ -925,7 +971,7 @@ retry:
 			return ERR_PTR(-EAGAIN);
 
 		mutex_lock(&c->bucket_lock);
-		b = mca_alloc(c, k, level, &op->cl);
+		b = mca_alloc(c, k, level);
 		mutex_unlock(&c->bucket_lock);
 
 		if (!b)
@@ -971,7 +1017,7 @@ static void btree_node_prefetch(struct cache_set *c, struct bkey *k, int level)
 	struct btree *b;
 
 	mutex_lock(&c->bucket_lock);
-	b = mca_alloc(c, k, level, NULL);
+	b = mca_alloc(c, k, level);
 	mutex_unlock(&c->bucket_lock);
 
 	if (!IS_ERR_OR_NULL(b)) {
@@ -982,17 +1028,12 @@ static void btree_node_prefetch(struct cache_set *c, struct bkey *k, int level)
 
 /* Btree alloc */
 
-static void btree_node_free(struct btree *b, struct btree_op *op)
+static void btree_node_free(struct btree *b)
 {
 	unsigned i;
 
 	trace_bcache_btree_node_free(b);
 
-	/*
-	 * The BUG_ON() in btree_node_get() implies that we must have a write
-	 * lock on parent to free or even invalidate a node
-	 */
-	BUG_ON(op->lock <= b->level);
 	BUG_ON(b == b->c->root);
 
 	if (btree_node_dirty(b))
@@ -1015,27 +1056,26 @@ static void btree_node_free(struct btree *b, struct btree_op *op)
 	mutex_unlock(&b->c->bucket_lock);
 }
 
-struct btree *bch_btree_node_alloc(struct cache_set *c, int level,
-				   struct closure *cl)
+struct btree *bch_btree_node_alloc(struct cache_set *c, int level, bool wait)
 {
 	BKEY_PADDED(key) k;
 	struct btree *b = ERR_PTR(-EAGAIN);
 
 	mutex_lock(&c->bucket_lock);
 retry:
-	if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, cl))
+	if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, wait))
 		goto err;
 
+	bkey_put(c, &k.key);
 	SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
 
-	b = mca_alloc(c, &k.key, level, cl);
+	b = mca_alloc(c, &k.key, level);
 	if (IS_ERR(b))
 		goto err_free;
 
 	if (!b) {
 		cache_bug(c,
 			"Tried to allocate bucket that was in btree cache");
-		__bkey_put(c, &k.key);
 		goto retry;
 	}
 
@@ -1048,7 +1088,6 @@ retry:
 	return b;
 err_free:
 	bch_bucket_free(c, &k.key);
-	__bkey_put(c, &k.key);
 err:
 	mutex_unlock(&c->bucket_lock);
 
@@ -1056,16 +1095,31 @@ err:
 	return b;
 }
 
-static struct btree *btree_node_alloc_replacement(struct btree *b,
-						  struct closure *cl)
+static struct btree *btree_node_alloc_replacement(struct btree *b, bool wait)
 {
-	struct btree *n = bch_btree_node_alloc(b->c, b->level, cl);
+	struct btree *n = bch_btree_node_alloc(b->c, b->level, wait);
 	if (!IS_ERR_OR_NULL(n))
 		bch_btree_sort_into(b, n);
 
 	return n;
 }
 
+static void make_btree_freeing_key(struct btree *b, struct bkey *k)
+{
+	unsigned i;
+
+	bkey_copy(k, &b->key);
+	bkey_copy_key(k, &ZERO_KEY);
+
+	for (i = 0; i < KEY_PTRS(k); i++) {
+		uint8_t g = PTR_BUCKET(b->c, k, i)->gen + 1;
+
+		SET_PTR_GEN(k, i, g);
+	}
+
+	atomic_inc(&b->c->prio_blocked);
+}
+
 /* Garbage collection */
 
 uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
@@ -1119,12 +1173,10 @@ uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
 
 #define btree_mark_key(b, k)	__bch_btree_mark_key(b->c, b->level, k)
 
-static int btree_gc_mark_node(struct btree *b, unsigned *keys,
-			      struct gc_stat *gc)
+static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
 {
 	uint8_t stale = 0;
-	unsigned last_dev = -1;
-	struct bcache_device *d = NULL;
+	unsigned keys = 0, good_keys = 0;
 	struct bkey *k;
 	struct btree_iter iter;
 	struct bset_tree *t;
@@ -1132,27 +1184,17 @@ static int btree_gc_mark_node(struct btree *b, unsigned *keys,
 	gc->nodes++;
 
 	for_each_key_filter(b, k, &iter, bch_ptr_invalid) {
-		if (last_dev != KEY_INODE(k)) {
-			last_dev = KEY_INODE(k);
-
-			d = KEY_INODE(k) < b->c->nr_uuids
-				? b->c->devices[last_dev]
-				: NULL;
-		}
-
 		stale = max(stale, btree_mark_key(b, k));
+		keys++;
 
 		if (bch_ptr_bad(b, k))
 			continue;
 
-		*keys += bkey_u64s(k);
-
 		gc->key_bytes += bkey_u64s(k);
 		gc->nkeys++;
+		good_keys++;
 
 		gc->data += KEY_SIZE(k);
-		if (KEY_DIRTY(k))
-			gc->dirty += KEY_SIZE(k);
 	}
 
 	for (t = b->sets; t <= &b->sets[b->nsets]; t++)
@@ -1161,78 +1203,74 @@ static int btree_gc_mark_node(struct btree *b, unsigned *keys,
 			     bkey_cmp(&b->key, &t->end) < 0,
 			     b, "found short btree key in gc");
 
-	return stale;
-}
-
-static struct btree *btree_gc_alloc(struct btree *b, struct bkey *k,
-				    struct btree_op *op)
-{
-	/*
-	 * We block priorities from being written for the duration of garbage
-	 * collection, so we can't sleep in btree_alloc() ->
-	 * bch_bucket_alloc_set(), or we'd risk deadlock - so we don't pass it
-	 * our closure.
-	 */
-	struct btree *n = btree_node_alloc_replacement(b, NULL);
-
-	if (!IS_ERR_OR_NULL(n)) {
-		swap(b, n);
-		__bkey_put(b->c, &b->key);
+	if (b->c->gc_always_rewrite)
+		return true;
 
-		memcpy(k->ptr, b->key.ptr,
-		       sizeof(uint64_t) * KEY_PTRS(&b->key));
+	if (stale > 10)
+		return true;
 
-		btree_node_free(n, op);
-		up_write(&n->lock);
-	}
+	if ((keys - good_keys) * 2 > keys)
+		return true;
 
-	return b;
+	return false;
 }
 
-/*
- * Leaving this at 2 until we've got incremental garbage collection done; it
- * could be higher (and has been tested with 4) except that garbage collection
- * could take much longer, adversely affecting latency.
- */
-#define GC_MERGE_NODES	2U
+#define GC_MERGE_NODES	4U
 
 struct gc_merge_info {
 	struct btree	*b;
-	struct bkey	*k;
 	unsigned	keys;
 };
 
-static void btree_gc_coalesce(struct btree *b, struct btree_op *op,
-			      struct gc_stat *gc, struct gc_merge_info *r)
+static int bch_btree_insert_node(struct btree *, struct btree_op *,
+				 struct keylist *, atomic_t *, struct bkey *);
+
+static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
+			     struct keylist *keylist, struct gc_stat *gc,
+			     struct gc_merge_info *r)
 {
-	unsigned nodes = 0, keys = 0, blocks;
-	int i;
+	unsigned i, nodes = 0, keys = 0, blocks;
+	struct btree *new_nodes[GC_MERGE_NODES];
+	struct closure cl;
+	struct bkey *k;
+
+	memset(new_nodes, 0, sizeof(new_nodes));
+	closure_init_stack(&cl);
 
-	while (nodes < GC_MERGE_NODES && r[nodes].b)
+	while (nodes < GC_MERGE_NODES && !IS_ERR_OR_NULL(r[nodes].b))
 		keys += r[nodes++].keys;
 
 	blocks = btree_default_blocks(b->c) * 2 / 3;
 
 	if (nodes < 2 ||
 	    __set_blocks(b->sets[0].data, keys, b->c) > blocks * (nodes - 1))
-		return;
-
-	for (i = nodes - 1; i >= 0; --i) {
-		if (r[i].b->written)
-			r[i].b = btree_gc_alloc(r[i].b, r[i].k, op);
+		return 0;
 
-		if (r[i].b->written)
-			return;
+	for (i = 0; i < nodes; i++) {
+		new_nodes[i] = btree_node_alloc_replacement(r[i].b, false);
+		if (IS_ERR_OR_NULL(new_nodes[i]))
+			goto out_nocoalesce;
 	}
 
 	for (i = nodes - 1; i > 0; --i) {
-		struct bset *n1 = r[i].b->sets->data;
-		struct bset *n2 = r[i - 1].b->sets->data;
+		struct bset *n1 = new_nodes[i]->sets->data;
+		struct bset *n2 = new_nodes[i - 1]->sets->data;
 		struct bkey *k, *last = NULL;
 
 		keys = 0;
 
-		if (i == 1) {
+		if (i > 1) {
+			for (k = n2->start;
+			     k < end(n2);
+			     k = bkey_next(k)) {
+				if (__set_blocks(n1, n1->keys + keys +
+						 bkey_u64s(k), b->c) > blocks)
+					break;
+
+				last = k;
+				keys += bkey_u64s(k);
+			}
+		} else {
 			/*
 			 * Last node we're not getting rid of - we're getting
 			 * rid of the node at r[0]. Have to try and fit all of
@@ -1241,37 +1279,27 @@ static void btree_gc_coalesce(struct btree *b, struct btree_op *op,
 			 * length keys (shouldn't be possible in practice,
 			 * though)
 			 */
-			if (__set_blocks(n1, n1->keys + r->keys,
-					 b->c) > btree_blocks(r[i].b))
-				return;
+			if (__set_blocks(n1, n1->keys + n2->keys,
+					 b->c) > btree_blocks(new_nodes[i]))
+				goto out_nocoalesce;
 
 			keys = n2->keys;
+			/* Take the key of the node we're getting rid of */
 			last = &r->b->key;
-		} else
-			for (k = n2->start;
-			     k < end(n2);
-			     k = bkey_next(k)) {
-				if (__set_blocks(n1, n1->keys + keys +
-						 bkey_u64s(k), b->c) > blocks)
-					break;
-
-				last = k;
-				keys += bkey_u64s(k);
-			}
+		}
 
 		BUG_ON(__set_blocks(n1, n1->keys + keys,
-				    b->c) > btree_blocks(r[i].b));
+				    b->c) > btree_blocks(new_nodes[i]));
 
-		if (last) {
-			bkey_copy_key(&r[i].b->key, last);
-			bkey_copy_key(r[i].k, last);
-		}
+		if (last)
+			bkey_copy_key(&new_nodes[i]->key, last);
 
 		memcpy(end(n1),
 		       n2->start,
 		       (void *) node(n2, keys) - (void *) n2->start);
 
 		n1->keys += keys;
+		r[i].keys = n1->keys;
 
 		memmove(n2->start,
 			node(n2, keys),
@@ -1279,95 +1307,176 @@ static void btree_gc_coalesce(struct btree *b, struct btree_op *op,
 
 		n2->keys -= keys;
 
-		r[i].keys	= n1->keys;
-		r[i - 1].keys	= n2->keys;
+		if (bch_keylist_realloc(keylist,
+					KEY_PTRS(&new_nodes[i]->key), b->c))
+			goto out_nocoalesce;
+
+		bch_btree_node_write(new_nodes[i], &cl);
+		bch_keylist_add(keylist, &new_nodes[i]->key);
 	}
 
-	btree_node_free(r->b, op);
-	up_write(&r->b->lock);
+	for (i = 0; i < nodes; i++) {
+		if (bch_keylist_realloc(keylist, KEY_PTRS(&r[i].b->key), b->c))
+			goto out_nocoalesce;
 
-	trace_bcache_btree_gc_coalesce(nodes);
+		make_btree_freeing_key(r[i].b, keylist->top);
+		bch_keylist_push(keylist);
+	}
+
+	/* We emptied out this node */
+	BUG_ON(new_nodes[0]->sets->data->keys);
+	btree_node_free(new_nodes[0]);
+	rw_unlock(true, new_nodes[0]);
+
+	closure_sync(&cl);
+
+	for (i = 0; i < nodes; i++) {
+		btree_node_free(r[i].b);
+		rw_unlock(true, r[i].b);
+
+		r[i].b = new_nodes[i];
+	}
+
+	bch_btree_insert_node(b, op, keylist, NULL, NULL);
+	BUG_ON(!bch_keylist_empty(keylist));
+
+	memmove(r, r + 1, sizeof(r[0]) * (nodes - 1));
+	r[nodes - 1].b = ERR_PTR(-EINTR);
 
+	trace_bcache_btree_gc_coalesce(nodes);
 	gc->nodes--;
-	nodes--;
 
-	memmove(&r[0], &r[1], sizeof(struct gc_merge_info) * nodes);
-	memset(&r[nodes], 0, sizeof(struct gc_merge_info));
+	/* Invalidated our iterator */
+	return -EINTR;
+
+out_nocoalesce:
+	closure_sync(&cl);
+
+	while ((k = bch_keylist_pop(keylist)))
+		if (!bkey_cmp(k, &ZERO_KEY))
+			atomic_dec(&b->c->prio_blocked);
+
+	for (i = 0; i < nodes; i++)
+		if (!IS_ERR_OR_NULL(new_nodes[i])) {
+			btree_node_free(new_nodes[i]);
+			rw_unlock(true, new_nodes[i]);
+		}
+	return 0;
 }
 
-static int btree_gc_recurse(struct btree *b, struct btree_op *op,
-			    struct closure *writes, struct gc_stat *gc)
+static unsigned btree_gc_count_keys(struct btree *b)
 {
-	void write(struct btree *r)
-	{
-		if (!r->written)
-			bch_btree_node_write(r, &op->cl);
-		else if (btree_node_dirty(r))
-			bch_btree_node_write(r, writes);
+	struct bkey *k;
+	struct btree_iter iter;
+	unsigned ret = 0;
 
-		up_write(&r->lock);
-	}
+	for_each_key_filter(b, k, &iter, bch_ptr_bad)
+		ret += bkey_u64s(k);
+
+	return ret;
+}
 
-	int ret = 0, stale;
+static int btree_gc_recurse(struct btree *b, struct btree_op *op,
+			    struct closure *writes, struct gc_stat *gc)
+{
 	unsigned i;
+	int ret = 0;
+	bool should_rewrite;
+	struct btree *n;
+	struct bkey *k;
+	struct keylist keys;
+	struct btree_iter iter;
 	struct gc_merge_info r[GC_MERGE_NODES];
+	struct gc_merge_info *last = r + GC_MERGE_NODES - 1;
 
-	memset(r, 0, sizeof(r));
+	bch_keylist_init(&keys);
+	bch_btree_iter_init(b, &iter, &b->c->gc_done);
 
-	while ((r->k = bch_next_recurse_key(b, &b->c->gc_done))) {
-		r->b = bch_btree_node_get(b->c, r->k, b->level - 1, op);
+	for (i = 0; i < GC_MERGE_NODES; i++)
+		r[i].b = ERR_PTR(-EINTR);
 
-		if (IS_ERR(r->b)) {
-			ret = PTR_ERR(r->b);
-			break;
+	while (1) {
+		k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
+		if (k) {
+			r->b = bch_btree_node_get(b->c, k, b->level - 1, true);
+			if (IS_ERR(r->b)) {
+				ret = PTR_ERR(r->b);
+				break;
+			}
+
+			r->keys = btree_gc_count_keys(r->b);
+
+			ret = btree_gc_coalesce(b, op, &keys, gc, r);
+			if (ret)
+				break;
 		}
 
-		r->keys	= 0;
-		stale = btree_gc_mark_node(r->b, &r->keys, gc);
+		if (!last->b)
+			break;
 
-		if (!b->written &&
-		    (r->b->level || stale > 10 ||
-		     b->c->gc_always_rewrite))
-			r->b = btree_gc_alloc(r->b, r->k, op);
+		if (!IS_ERR(last->b)) {
+			should_rewrite = btree_gc_mark_node(last->b, gc);
+			if (should_rewrite) {
+				n = btree_node_alloc_replacement(last->b,
+								 false);
 
-		if (r->b->level)
-			ret = btree_gc_recurse(r->b, op, writes, gc);
+				if (!IS_ERR_OR_NULL(n)) {
+					bch_btree_node_write_sync(n);
+					bch_keylist_add(&keys, &n->key);
 
-		if (ret) {
-			write(r->b);
-			break;
-		}
+					make_btree_freeing_key(last->b,
+							       keys.top);
+					bch_keylist_push(&keys);
+
+					btree_node_free(last->b);
+
+					bch_btree_insert_node(b, op, &keys,
+							      NULL, NULL);
+					BUG_ON(!bch_keylist_empty(&keys));
 
-		bkey_copy_key(&b->c->gc_done, r->k);
+					rw_unlock(true, last->b);
+					last->b = n;
 
-		if (!b->written)
-			btree_gc_coalesce(b, op, gc, r);
+					/* Invalidated our iterator */
+					ret = -EINTR;
+					break;
+				}
+			}
 
-		if (r[GC_MERGE_NODES - 1].b)
-			write(r[GC_MERGE_NODES - 1].b);
+			if (last->b->level) {
+				ret = btree_gc_recurse(last->b, op, writes, gc);
+				if (ret)
+					break;
+			}
 
-		memmove(&r[1], &r[0],
-			sizeof(struct gc_merge_info) * (GC_MERGE_NODES - 1));
+			bkey_copy_key(&b->c->gc_done, &last->b->key);
+
+			/*
+			 * Must flush leaf nodes before gc ends, since replace
+			 * operations aren't journalled
+			 */
+			if (btree_node_dirty(last->b))
+				bch_btree_node_write(last->b, writes);
+			rw_unlock(true, last->b);
+		}
+
+		memmove(r + 1, r, sizeof(r[0]) * (GC_MERGE_NODES - 1));
+		r->b = NULL;
 
-		/* When we've got incremental GC working, we'll want to do
-		 * if (should_resched())
-		 *	return -EAGAIN;
-		 */
-		cond_resched();
-#if 0
 		if (need_resched()) {
 			ret = -EAGAIN;
 			break;
 		}
-#endif
 	}
 
-	for (i = 1; i < GC_MERGE_NODES && r[i].b; i++)
-		write(r[i].b);
+	for (i = 0; i < GC_MERGE_NODES; i++)
+		if (!IS_ERR_OR_NULL(r[i].b)) {
+			if (btree_node_dirty(r[i].b))
+				bch_btree_node_write(r[i].b, writes);
+			rw_unlock(true, r[i].b);
+		}
 
-	/* Might have freed some children, must remove their keys */
-	if (!b->written)
-		bch_btree_sort(b);
+	bch_keylist_free(&keys);
 
 	return ret;
 }
@@ -1376,29 +1485,31 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
 			     struct closure *writes, struct gc_stat *gc)
 {
 	struct btree *n = NULL;
-	unsigned keys = 0;
-	int ret = 0, stale = btree_gc_mark_node(b, &keys, gc);
-
-	if (b->level || stale > 10)
-		n = btree_node_alloc_replacement(b, NULL);
+	int ret = 0;
+	bool should_rewrite;
 
-	if (!IS_ERR_OR_NULL(n))
-		swap(b, n);
+	should_rewrite = btree_gc_mark_node(b, gc);
+	if (should_rewrite) {
+		n = btree_node_alloc_replacement(b, false);
 
-	if (b->level)
-		ret = btree_gc_recurse(b, op, writes, gc);
+		if (!IS_ERR_OR_NULL(n)) {
+			bch_btree_node_write_sync(n);
+			bch_btree_set_root(n);
+			btree_node_free(b);
+			rw_unlock(true, n);
 
-	if (!b->written || btree_node_dirty(b)) {
-		bch_btree_node_write(b, n ? &op->cl : NULL);
+			return -EINTR;
+		}
 	}
 
-	if (!IS_ERR_OR_NULL(n)) {
-		closure_sync(&op->cl);
-		bch_btree_set_root(b);
-		btree_node_free(n, op);
-		rw_unlock(true, b);
+	if (b->level) {
+		ret = btree_gc_recurse(b, op, writes, gc);
+		if (ret)
+			return ret;
 	}
 
+	bkey_copy_key(&b->c->gc_done, &b->key);
+
 	return ret;
 }
 
@@ -1479,9 +1590,8 @@ size_t bch_btree_gc_finish(struct cache_set *c)
 	return available;
 }
 
-static void bch_btree_gc(struct closure *cl)
+static void bch_btree_gc(struct cache_set *c)
 {
-	struct cache_set *c = container_of(cl, struct cache_set, gc.cl);
 	int ret;
 	unsigned long available;
 	struct gc_stat stats;
@@ -1493,47 +1603,73 @@ static void bch_btree_gc(struct closure *cl)
 
 	memset(&stats, 0, sizeof(struct gc_stat));
 	closure_init_stack(&writes);
-	bch_btree_op_init_stack(&op);
-	op.lock = SHRT_MAX;
+	bch_btree_op_init(&op, SHRT_MAX);
 
 	btree_gc_start(c);
 
-	atomic_inc(&c->prio_blocked);
-
-	ret = btree_root(gc_root, c, &op, &writes, &stats);
-	closure_sync(&op.cl);
-	closure_sync(&writes);
-
-	if (ret) {
-		pr_warn("gc failed!");
-		continue_at(cl, bch_btree_gc, bch_gc_wq);
-	}
+	do {
+		ret = btree_root(gc_root, c, &op, &writes, &stats);
+		closure_sync(&writes);
 
-	/* Possibly wait for new UUIDs or whatever to hit disk */
-	bch_journal_meta(c, &op.cl);
-	closure_sync(&op.cl);
+		if (ret && ret != -EAGAIN)
+			pr_warn("gc failed!");
+	} while (ret);
 
 	available = bch_btree_gc_finish(c);
-
-	atomic_dec(&c->prio_blocked);
 	wake_up_allocators(c);
 
 	bch_time_stats_update(&c->btree_gc_time, start_time);
 
 	stats.key_bytes *= sizeof(uint64_t);
-	stats.dirty	<<= 9;
 	stats.data	<<= 9;
 	stats.in_use	= (c->nbuckets - available) * 100 / c->nbuckets;
 	memcpy(&c->gc_stats, &stats, sizeof(struct gc_stat));
 
 	trace_bcache_gc_end(c);
 
-	continue_at(cl, bch_moving_gc, bch_gc_wq);
+	bch_moving_gc(c);
+}
+
+static int bch_gc_thread(void *arg)
+{
+	struct cache_set *c = arg;
+	struct cache *ca;
+	unsigned i;
+
+	while (1) {
+again:
+		bch_btree_gc(c);
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&c->bucket_lock);
+
+		for_each_cache(ca, c, i)
+			if (ca->invalidate_needs_gc) {
+				mutex_unlock(&c->bucket_lock);
+				set_current_state(TASK_RUNNING);
+				goto again;
+			}
+
+		mutex_unlock(&c->bucket_lock);
+
+		try_to_freeze();
+		schedule();
+	}
+
+	return 0;
 }
 
-void bch_queue_gc(struct cache_set *c)
+int bch_gc_thread_start(struct cache_set *c)
 {
-	closure_trylock_call(&c->gc.cl, bch_btree_gc, bch_gc_wq, &c->cl);
+	c->gc_thread = kthread_create(bch_gc_thread, c, "bcache_gc");
+	if (IS_ERR(c->gc_thread))
+		return PTR_ERR(c->gc_thread);
+
+	set_task_state(c->gc_thread, TASK_INTERRUPTIBLE);
+	return 0;
 }
 
 /* Initial partial gc */
@@ -1541,9 +1677,9 @@ void bch_queue_gc(struct cache_set *c)
 static int bch_btree_check_recurse(struct btree *b, struct btree_op *op,
 				   unsigned long **seen)
 {
-	int ret;
+	int ret = 0;
 	unsigned i;
-	struct bkey *k;
+	struct bkey *k, *p = NULL;
 	struct bucket *g;
 	struct btree_iter iter;
 
@@ -1570,31 +1706,32 @@ static int bch_btree_check_recurse(struct btree *b, struct btree_op *op,
 	}
 
 	if (b->level) {
-		k = bch_next_recurse_key(b, &ZERO_KEY);
+		bch_btree_iter_init(b, &iter, NULL);
 
-		while (k) {
-			struct bkey *p = bch_next_recurse_key(b, k);
-			if (p)
-				btree_node_prefetch(b->c, p, b->level - 1);
+		do {
+			k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
+			if (k)
+				btree_node_prefetch(b->c, k, b->level - 1);
 
-			ret = btree(check_recurse, k, b, op, seen);
-			if (ret)
-				return ret;
+			if (p)
+				ret = btree(check_recurse, p, b, op, seen);
 
-			k = p;
-		}
+			p = k;
+		} while (p && !ret);
 	}
 
 	return 0;
 }
 
-int bch_btree_check(struct cache_set *c, struct btree_op *op)
+int bch_btree_check(struct cache_set *c)
 {
 	int ret = -ENOMEM;
 	unsigned i;
 	unsigned long *seen[MAX_CACHES_PER_SET];
+	struct btree_op op;
 
 	memset(seen, 0, sizeof(seen));
+	bch_btree_op_init(&op, SHRT_MAX);
 
 	for (i = 0; c->cache[i]; i++) {
 		size_t n = DIV_ROUND_UP(c->cache[i]->sb.nbuckets, 8);
@@ -1606,7 +1743,7 @@ int bch_btree_check(struct cache_set *c, struct btree_op *op)
 		memset(seen[i], 0xFF, n);
 	}
 
-	ret = btree_root(check_recurse, c, op, seen);
+	ret = btree_root(check_recurse, c, &op, seen);
 err:
 	for (i = 0; i < MAX_CACHES_PER_SET; i++)
 		kfree(seen[i]);
@@ -1628,10 +1765,9 @@ static void shift_keys(struct btree *b, struct bkey *where, struct bkey *insert)
 	bch_bset_fix_lookup_table(b, where);
 }
 
-static bool fix_overlapping_extents(struct btree *b,
-				    struct bkey *insert,
+static bool fix_overlapping_extents(struct btree *b, struct bkey *insert,
 				    struct btree_iter *iter,
-				    struct btree_op *op)
+				    struct bkey *replace_key)
 {
 	void subtract_dirty(struct bkey *k, uint64_t offset, int sectors)
 	{
@@ -1659,39 +1795,38 @@ static bool fix_overlapping_extents(struct btree *b,
 		 * We might overlap with 0 size extents; we can't skip these
 		 * because if they're in the set we're inserting to we have to
 		 * adjust them so they don't overlap with the key we're
-		 * inserting. But we don't want to check them for BTREE_REPLACE
+		 * inserting. But we don't want to check them for replace
 		 * operations.
 		 */
 
-		if (op->type == BTREE_REPLACE &&
-		    KEY_SIZE(k)) {
+		if (replace_key && KEY_SIZE(k)) {
 			/*
 			 * k might have been split since we inserted/found the
 			 * key we're replacing
 			 */
 			unsigned i;
 			uint64_t offset = KEY_START(k) -
-				KEY_START(&op->replace);
+				KEY_START(replace_key);
 
 			/* But it must be a subset of the replace key */
-			if (KEY_START(k) < KEY_START(&op->replace) ||
-			    KEY_OFFSET(k) > KEY_OFFSET(&op->replace))
+			if (KEY_START(k) < KEY_START(replace_key) ||
+			    KEY_OFFSET(k) > KEY_OFFSET(replace_key))
 				goto check_failed;
 
 			/* We didn't find a key that we were supposed to */
 			if (KEY_START(k) > KEY_START(insert) + sectors_found)
 				goto check_failed;
 
-			if (KEY_PTRS(&op->replace) != KEY_PTRS(k))
+			if (KEY_PTRS(replace_key) != KEY_PTRS(k))
 				goto check_failed;
 
 			/* skip past gen */
 			offset <<= 8;
 
-			BUG_ON(!KEY_PTRS(&op->replace));
+			BUG_ON(!KEY_PTRS(replace_key));
 
-			for (i = 0; i < KEY_PTRS(&op->replace); i++)
-				if (k->ptr[i] != op->replace.ptr[i] + offset)
+			for (i = 0; i < KEY_PTRS(replace_key); i++)
+				if (k->ptr[i] != replace_key->ptr[i] + offset)
 					goto check_failed;
 
 			sectors_found = KEY_OFFSET(k) - KEY_START(insert);
@@ -1742,6 +1877,9 @@ static bool fix_overlapping_extents(struct btree *b,
 		if (bkey_cmp(insert, k) < 0) {
 			bch_cut_front(insert, k);
 		} else {
+			if (bkey_cmp(&START_KEY(insert), &START_KEY(k)) > 0)
+				old_offset = KEY_START(insert);
+
 			if (bkey_written(b, k) &&
 			    bkey_cmp(&START_KEY(insert), &START_KEY(k)) <= 0) {
 				/*
@@ -1759,9 +1897,8 @@ static bool fix_overlapping_extents(struct btree *b,
 	}
 
 check_failed:
-	if (op->type == BTREE_REPLACE) {
+	if (replace_key) {
 		if (!sectors_found) {
-			op->insert_collision = true;
 			return true;
 		} else if (sectors_found < KEY_SIZE(insert)) {
 			SET_KEY_OFFSET(insert, KEY_OFFSET(insert) -
@@ -1774,7 +1911,7 @@ check_failed:
 }
 
 static bool btree_insert_key(struct btree *b, struct btree_op *op,
-			     struct bkey *k)
+			     struct bkey *k, struct bkey *replace_key)
 {
 	struct bset *i = b->sets[b->nsets].data;
 	struct bkey *m, *prev;
@@ -1786,22 +1923,23 @@ static bool btree_insert_key(struct btree *b, struct btree_op *op,
 
 	if (!b->level) {
 		struct btree_iter iter;
-		struct bkey search = KEY(KEY_INODE(k), KEY_START(k), 0);
 
 		/*
 		 * bset_search() returns the first key that is strictly greater
 		 * than the search key - but for back merging, we want to find
-		 * the first key that is greater than or equal to KEY_START(k) -
-		 * unless KEY_START(k) is 0.
+		 * the previous key.
 		 */
-		if (KEY_OFFSET(&search))
-			SET_KEY_OFFSET(&search, KEY_OFFSET(&search) - 1);
-
 		prev = NULL;
-		m = bch_btree_iter_init(b, &iter, &search);
+		m = bch_btree_iter_init(b, &iter, PRECEDING_KEY(&START_KEY(k)));
 
-		if (fix_overlapping_extents(b, k, &iter, op))
+		if (fix_overlapping_extents(b, k, &iter, replace_key)) {
+			op->insert_collision = true;
 			return false;
+		}
+
+		if (KEY_DIRTY(k))
+			bcache_dev_sectors_dirty_add(b->c, KEY_INODE(k),
+						     KEY_START(k), KEY_SIZE(k));
 
 		while (m != end(i) &&
 		       bkey_cmp(k, &START_KEY(m)) > 0)
@@ -1825,84 +1963,80 @@ static bool btree_insert_key(struct btree *b, struct btree_op *op,
 		if (m != end(i) &&
 		    bch_bkey_try_merge(b, k, m))
 			goto copy;
-	} else
+	} else {
+		BUG_ON(replace_key);
 		m = bch_bset_search(b, &b->sets[b->nsets], k);
+	}
 
 insert:	shift_keys(b, m, k);
 copy:	bkey_copy(m, k);
 merged:
-	if (KEY_DIRTY(k))
-		bcache_dev_sectors_dirty_add(b->c, KEY_INODE(k),
-					     KEY_START(k), KEY_SIZE(k));
-
-	bch_check_keys(b, "%u for %s", status, op_type(op));
+	bch_check_keys(b, "%u for %s", status,
+		       replace_key ? "replace" : "insert");
 
 	if (b->level && !KEY_OFFSET(k))
 		btree_current_write(b)->prio_blocked++;
 
-	trace_bcache_btree_insert_key(b, k, op->type, status);
+	trace_bcache_btree_insert_key(b, k, replace_key != NULL, status);
 
 	return true;
 }
 
-static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op)
+static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op,
+				  struct keylist *insert_keys,
+				  struct bkey *replace_key)
 {
 	bool ret = false;
-	struct bkey *k;
-	unsigned oldsize = bch_count_data(b);
-
-	while ((k = bch_keylist_pop(&op->keys))) {
-		bkey_put(b->c, k, b->level);
-		ret |= btree_insert_key(b, op, k);
-	}
-
-	BUG_ON(bch_count_data(b) < oldsize);
-	return ret;
-}
+	int oldsize = bch_count_data(b);
 
-bool bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
-				   struct bio *bio)
-{
-	bool ret = false;
-	uint64_t btree_ptr = b->key.ptr[0];
-	unsigned long seq = b->seq;
-	BKEY_PADDED(k) tmp;
+	while (!bch_keylist_empty(insert_keys)) {
+		struct bset *i = write_block(b);
+		struct bkey *k = insert_keys->keys;
 
-	rw_unlock(false, b);
-	rw_lock(true, b, b->level);
+		if (b->written + __set_blocks(i, i->keys + bkey_u64s(k), b->c)
+		    > btree_blocks(b))
+			break;
 
-	if (b->key.ptr[0] != btree_ptr ||
-	    b->seq != seq + 1 ||
-	    should_split(b))
-		goto out;
+		if (bkey_cmp(k, &b->key) <= 0) {
+			if (!b->level)
+				bkey_put(b->c, k);
 
-	op->replace = KEY(op->inode, bio_end_sector(bio), bio_sectors(bio));
+			ret |= btree_insert_key(b, op, k, replace_key);
+			bch_keylist_pop_front(insert_keys);
+		} else if (bkey_cmp(&START_KEY(k), &b->key) < 0) {
+			BKEY_PADDED(key) temp;
+			bkey_copy(&temp.key, insert_keys->keys);
 
-	SET_KEY_PTRS(&op->replace, 1);
-	get_random_bytes(&op->replace.ptr[0], sizeof(uint64_t));
+			bch_cut_back(&b->key, &temp.key);
+			bch_cut_front(&b->key, insert_keys->keys);
 
-	SET_PTR_DEV(&op->replace, 0, PTR_CHECK_DEV);
+			ret |= btree_insert_key(b, op, &temp.key, replace_key);
+			break;
+		} else {
+			break;
+		}
+	}
 
-	bkey_copy(&tmp.k, &op->replace);
+	BUG_ON(!bch_keylist_empty(insert_keys) && b->level);
 
-	BUG_ON(op->type != BTREE_INSERT);
-	BUG_ON(!btree_insert_key(b, op, &tmp.k));
-	ret = true;
-out:
-	downgrade_write(&b->lock);
+	BUG_ON(bch_count_data(b) < oldsize);
 	return ret;
 }
 
-static int btree_split(struct btree *b, struct btree_op *op)
+static int btree_split(struct btree *b, struct btree_op *op,
+		       struct keylist *insert_keys,
+		       struct bkey *replace_key)
 {
-	bool split, root = b == b->c->root;
+	bool split;
 	struct btree *n1, *n2 = NULL, *n3 = NULL;
 	uint64_t start_time = local_clock();
+	struct closure cl;
+	struct keylist parent_keys;
 
-	if (b->level)
-		set_closure_blocking(&op->cl);
+	closure_init_stack(&cl);
+	bch_keylist_init(&parent_keys);
 
-	n1 = btree_node_alloc_replacement(b, &op->cl);
+	n1 = btree_node_alloc_replacement(b, true);
 	if (IS_ERR(n1))
 		goto err;
 
@@ -1913,19 +2047,20 @@ static int btree_split(struct btree *b, struct btree_op *op)
 
 		trace_bcache_btree_node_split(b, n1->sets[0].data->keys);
 
-		n2 = bch_btree_node_alloc(b->c, b->level, &op->cl);
+		n2 = bch_btree_node_alloc(b->c, b->level, true);
 		if (IS_ERR(n2))
 			goto err_free1;
 
-		if (root) {
-			n3 = bch_btree_node_alloc(b->c, b->level + 1, &op->cl);
+		if (!b->parent) {
+			n3 = bch_btree_node_alloc(b->c, b->level + 1, true);
 			if (IS_ERR(n3))
 				goto err_free2;
 		}
 
-		bch_btree_insert_keys(n1, op);
+		bch_btree_insert_keys(n1, op, insert_keys, replace_key);
 
-		/* Has to be a linear search because we don't have an auxiliary
+		/*
+		 * Has to be a linear search because we don't have an auxiliary
 		 * search tree yet
 		 */
 
@@ -1944,60 +2079,57 @@ static int btree_split(struct btree *b, struct btree_op *op)
 
 		bkey_copy_key(&n2->key, &b->key);
 
-		bch_keylist_add(&op->keys, &n2->key);
-		bch_btree_node_write(n2, &op->cl);
+		bch_keylist_add(&parent_keys, &n2->key);
+		bch_btree_node_write(n2, &cl);
 		rw_unlock(true, n2);
 	} else {
 		trace_bcache_btree_node_compact(b, n1->sets[0].data->keys);
 
-		bch_btree_insert_keys(n1, op);
+		bch_btree_insert_keys(n1, op, insert_keys, replace_key);
 	}
 
-	bch_keylist_add(&op->keys, &n1->key);
-	bch_btree_node_write(n1, &op->cl);
+	bch_keylist_add(&parent_keys, &n1->key);
+	bch_btree_node_write(n1, &cl);
 
 	if (n3) {
+		/* Depth increases, make a new root */
 		bkey_copy_key(&n3->key, &MAX_KEY);
-		bch_btree_insert_keys(n3, op);
-		bch_btree_node_write(n3, &op->cl);
+		bch_btree_insert_keys(n3, op, &parent_keys, NULL);
+		bch_btree_node_write(n3, &cl);
 
-		closure_sync(&op->cl);
+		closure_sync(&cl);
 		bch_btree_set_root(n3);
 		rw_unlock(true, n3);
-	} else if (root) {
-		op->keys.top = op->keys.bottom;
-		closure_sync(&op->cl);
-		bch_btree_set_root(n1);
-	} else {
-		unsigned i;
 
-		bkey_copy(op->keys.top, &b->key);
-		bkey_copy_key(op->keys.top, &ZERO_KEY);
+		btree_node_free(b);
+	} else if (!b->parent) {
+		/* Root filled up but didn't need to be split */
+		closure_sync(&cl);
+		bch_btree_set_root(n1);
 
-		for (i = 0; i < KEY_PTRS(&b->key); i++) {
-			uint8_t g = PTR_BUCKET(b->c, &b->key, i)->gen + 1;
+		btree_node_free(b);
+	} else {
+		/* Split a non root node */
+		closure_sync(&cl);
+		make_btree_freeing_key(b, parent_keys.top);
+		bch_keylist_push(&parent_keys);
 
-			SET_PTR_GEN(op->keys.top, i, g);
-		}
+		btree_node_free(b);
 
-		bch_keylist_push(&op->keys);
-		closure_sync(&op->cl);
-		atomic_inc(&b->c->prio_blocked);
+		bch_btree_insert_node(b->parent, op, &parent_keys, NULL, NULL);
+		BUG_ON(!bch_keylist_empty(&parent_keys));
 	}
 
 	rw_unlock(true, n1);
-	btree_node_free(b, op);
 
 	bch_time_stats_update(&b->c->btree_split_time, start_time);
 
 	return 0;
 err_free2:
-	__bkey_put(n2->c, &n2->key);
-	btree_node_free(n2, op);
+	btree_node_free(n2);
 	rw_unlock(true, n2);
 err_free1:
-	__bkey_put(n1->c, &n1->key);
-	btree_node_free(n1, op);
+	btree_node_free(n1);
 	rw_unlock(true, n1);
 err:
 	if (n3 == ERR_PTR(-EAGAIN) ||
@@ -2009,116 +2141,126 @@ err:
 	return -ENOMEM;
 }
 
-static int bch_btree_insert_recurse(struct btree *b, struct btree_op *op,
-				    struct keylist *stack_keys)
+static int bch_btree_insert_node(struct btree *b, struct btree_op *op,
+				 struct keylist *insert_keys,
+				 atomic_t *journal_ref,
+				 struct bkey *replace_key)
 {
-	if (b->level) {
-		int ret;
-		struct bkey *insert = op->keys.bottom;
-		struct bkey *k = bch_next_recurse_key(b, &START_KEY(insert));
-
-		if (!k) {
-			btree_bug(b, "no key to recurse on at level %i/%i",
-				  b->level, b->c->root->level);
+	BUG_ON(b->level && replace_key);
 
-			op->keys.top = op->keys.bottom;
-			return -EIO;
+	if (should_split(b)) {
+		if (current->bio_list) {
+			op->lock = b->c->root->level + 1;
+			return -EAGAIN;
+		} else if (op->lock <= b->c->root->level) {
+			op->lock = b->c->root->level + 1;
+			return -EINTR;
+		} else {
+			/* Invalidated all iterators */
+			return btree_split(b, op, insert_keys, replace_key) ?:
+				-EINTR;
 		}
+	} else {
+		BUG_ON(write_block(b) != b->sets[b->nsets].data);
 
-		if (bkey_cmp(insert, k) > 0) {
-			unsigned i;
-
-			if (op->type == BTREE_REPLACE) {
-				__bkey_put(b->c, insert);
-				op->keys.top = op->keys.bottom;
-				op->insert_collision = true;
-				return 0;
-			}
+		if (bch_btree_insert_keys(b, op, insert_keys, replace_key)) {
+			if (!b->level)
+				bch_btree_leaf_dirty(b, journal_ref);
+			else
+				bch_btree_node_write_sync(b);
+		}
 
-			for (i = 0; i < KEY_PTRS(insert); i++)
-				atomic_inc(&PTR_BUCKET(b->c, insert, i)->pin);
+		return 0;
+	}
+}
 
-			bkey_copy(stack_keys->top, insert);
+int bch_btree_insert_check_key(struct btree *b, struct btree_op *op,
+			       struct bkey *check_key)
+{
+	int ret = -EINTR;
+	uint64_t btree_ptr = b->key.ptr[0];
+	unsigned long seq = b->seq;
+	struct keylist insert;
+	bool upgrade = op->lock == -1;
 
-			bch_cut_back(k, insert);
-			bch_cut_front(k, stack_keys->top);
+	bch_keylist_init(&insert);
 
-			bch_keylist_push(stack_keys);
-		}
+	if (upgrade) {
+		rw_unlock(false, b);
+		rw_lock(true, b, b->level);
 
-		ret = btree(insert_recurse, k, b, op, stack_keys);
-		if (ret)
-			return ret;
+		if (b->key.ptr[0] != btree_ptr ||
+		    b->seq != seq + 1)
+			goto out;
 	}
 
-	if (!bch_keylist_empty(&op->keys)) {
-		if (should_split(b)) {
-			if (op->lock <= b->c->root->level) {
-				BUG_ON(b->level);
-				op->lock = b->c->root->level + 1;
-				return -EINTR;
-			}
-			return btree_split(b, op);
-		}
+	SET_KEY_PTRS(check_key, 1);
+	get_random_bytes(&check_key->ptr[0], sizeof(uint64_t));
 
-		BUG_ON(write_block(b) != b->sets[b->nsets].data);
+	SET_PTR_DEV(check_key, 0, PTR_CHECK_DEV);
 
-		if (bch_btree_insert_keys(b, op)) {
-			if (!b->level)
-				bch_btree_leaf_dirty(b, op);
-			else
-				bch_btree_node_write(b, &op->cl);
-		}
-	}
+	bch_keylist_add(&insert, check_key);
 
-	return 0;
+	ret = bch_btree_insert_node(b, op, &insert, NULL, NULL);
+
+	BUG_ON(!ret && !bch_keylist_empty(&insert));
+out:
+	if (upgrade)
+		downgrade_write(&b->lock);
+	return ret;
 }
 
-int bch_btree_insert(struct btree_op *op, struct cache_set *c)
+struct btree_insert_op {
+	struct btree_op	op;
+	struct keylist	*keys;
+	atomic_t	*journal_ref;
+	struct bkey	*replace_key;
+};
+
+int btree_insert_fn(struct btree_op *b_op, struct btree *b)
 {
-	int ret = 0;
-	struct keylist stack_keys;
+	struct btree_insert_op *op = container_of(b_op,
+					struct btree_insert_op, op);
 
-	/*
-	 * Don't want to block with the btree locked unless we have to,
-	 * otherwise we get deadlocks with try_harder and between split/gc
-	 */
-	clear_closure_blocking(&op->cl);
-
-	BUG_ON(bch_keylist_empty(&op->keys));
-	bch_keylist_copy(&stack_keys, &op->keys);
-	bch_keylist_init(&op->keys);
-
-	while (!bch_keylist_empty(&stack_keys) ||
-	       !bch_keylist_empty(&op->keys)) {
-		if (bch_keylist_empty(&op->keys)) {
-			bch_keylist_add(&op->keys,
-					bch_keylist_pop(&stack_keys));
-			op->lock = 0;
-		}
+	int ret = bch_btree_insert_node(b, &op->op, op->keys,
+					op->journal_ref, op->replace_key);
+	if (ret && !bch_keylist_empty(op->keys))
+		return ret;
+	else
+		return MAP_DONE;
+}
 
-		ret = btree_root(insert_recurse, c, op, &stack_keys);
+int bch_btree_insert(struct cache_set *c, struct keylist *keys,
+		     atomic_t *journal_ref, struct bkey *replace_key)
+{
+	struct btree_insert_op op;
+	int ret = 0;
 
-		if (ret == -EAGAIN) {
-			ret = 0;
-			closure_sync(&op->cl);
-		} else if (ret) {
-			struct bkey *k;
+	BUG_ON(current->bio_list);
+	BUG_ON(bch_keylist_empty(keys));
+
+	bch_btree_op_init(&op.op, 0);
+	op.keys		= keys;
+	op.journal_ref	= journal_ref;
+	op.replace_key	= replace_key;
+
+	while (!ret && !bch_keylist_empty(keys)) {
+		op.op.lock = 0;
+		ret = bch_btree_map_leaf_nodes(&op.op, c,
+					       &START_KEY(keys->keys),
+					       btree_insert_fn);
+	}
 
-			pr_err("error %i trying to insert key for %s",
-			       ret, op_type(op));
+	if (ret) {
+		struct bkey *k;
 
-			while ((k = bch_keylist_pop(&stack_keys) ?:
-				    bch_keylist_pop(&op->keys)))
-				bkey_put(c, k, 0);
-		}
-	}
+		pr_err("error %i", ret);
 
-	bch_keylist_free(&stack_keys);
+		while ((k = bch_keylist_pop(keys)))
+			bkey_put(c, k);
+	} else if (op.op.insert_collision)
+		ret = -ESRCH;
 
-	if (op->journal)
-		atomic_dec_bug(op->journal);
-	op->journal = NULL;
 	return ret;
 }
 
@@ -2141,132 +2283,81 @@ void bch_btree_set_root(struct btree *b)
 	mutex_unlock(&b->c->bucket_lock);
 
 	b->c->root = b;
-	__bkey_put(b->c, &b->key);
 
 	bch_journal_meta(b->c, &cl);
 	closure_sync(&cl);
 }
 
-/* Cache lookup */
+/* Map across nodes or keys */
 
-static int submit_partial_cache_miss(struct btree *b, struct btree_op *op,
-				     struct bkey *k)
+static int bch_btree_map_nodes_recurse(struct btree *b, struct btree_op *op,
+				       struct bkey *from,
+				       btree_map_nodes_fn *fn, int flags)
 {
-	struct search *s = container_of(op, struct search, op);
-	struct bio *bio = &s->bio.bio;
-	int ret = 0;
+	int ret = MAP_CONTINUE;
+
+	if (b->level) {
+		struct bkey *k;
+		struct btree_iter iter;
 
-	while (!ret &&
-	       !op->lookup_done) {
-		unsigned sectors = INT_MAX;
+		bch_btree_iter_init(b, &iter, from);
 
-		if (KEY_INODE(k) == op->inode) {
-			if (KEY_START(k) <= bio->bi_sector)
-				break;
+		while ((k = bch_btree_iter_next_filter(&iter, b,
+						       bch_ptr_bad))) {
+			ret = btree(map_nodes_recurse, k, b,
+				    op, from, fn, flags);
+			from = NULL;
 
-			sectors = min_t(uint64_t, sectors,
-					KEY_START(k) - bio->bi_sector);
+			if (ret != MAP_CONTINUE)
+				return ret;
 		}
-
-		ret = s->d->cache_miss(b, s, bio, sectors);
 	}
 
+	if (!b->level || flags == MAP_ALL_NODES)
+		ret = fn(op, b);
+
 	return ret;
 }
 
-/*
- * Read from a single key, handling the initial cache miss if the key starts in
- * the middle of the bio
- */
-static int submit_partial_cache_hit(struct btree *b, struct btree_op *op,
-				    struct bkey *k)
+int __bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
+			  struct bkey *from, btree_map_nodes_fn *fn, int flags)
 {
-	struct search *s = container_of(op, struct search, op);
-	struct bio *bio = &s->bio.bio;
-	unsigned ptr;
-	struct bio *n;
-
-	int ret = submit_partial_cache_miss(b, op, k);
-	if (ret || op->lookup_done)
-		return ret;
-
-	/* XXX: figure out best pointer - for multiple cache devices */
-	ptr = 0;
-
-	PTR_BUCKET(b->c, k, ptr)->prio = INITIAL_PRIO;
-
-	while (!op->lookup_done &&
-	       KEY_INODE(k) == op->inode &&
-	       bio->bi_sector < KEY_OFFSET(k)) {
-		struct bkey *bio_key;
-		sector_t sector = PTR_OFFSET(k, ptr) +
-			(bio->bi_sector - KEY_START(k));
-		unsigned sectors = min_t(uint64_t, INT_MAX,
-					 KEY_OFFSET(k) - bio->bi_sector);
-
-		n = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
-		if (n == bio)
-			op->lookup_done = true;
-
-		bio_key = &container_of(n, struct bbio, bio)->key;
-
-		/*
-		 * The bucket we're reading from might be reused while our bio
-		 * is in flight, and we could then end up reading the wrong
-		 * data.
-		 *
-		 * We guard against this by checking (in cache_read_endio()) if
-		 * the pointer is stale again; if so, we treat it as an error
-		 * and reread from the backing device (but we don't pass that
-		 * error up anywhere).
-		 */
-
-		bch_bkey_copy_single_ptr(bio_key, k, ptr);
-		SET_PTR_OFFSET(bio_key, 0, sector);
-
-		n->bi_end_io	= bch_cache_read_endio;
-		n->bi_private	= &s->cl;
-
-		__bch_submit_bbio(n, b->c);
-	}
-
-	return 0;
+	return btree_root(map_nodes_recurse, c, op, from, fn, flags);
 }
 
-int bch_btree_search_recurse(struct btree *b, struct btree_op *op)
+static int bch_btree_map_keys_recurse(struct btree *b, struct btree_op *op,
+				      struct bkey *from, btree_map_keys_fn *fn,
+				      int flags)
 {
-	struct search *s = container_of(op, struct search, op);
-	struct bio *bio = &s->bio.bio;
-
-	int ret = 0;
+	int ret = MAP_CONTINUE;
 	struct bkey *k;
 	struct btree_iter iter;
-	bch_btree_iter_init(b, &iter, &KEY(op->inode, bio->bi_sector, 0));
 
-	do {
-		k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
-		if (!k) {
-			/*
-			 * b->key would be exactly what we want, except that
-			 * pointers to btree nodes have nonzero size - we
-			 * wouldn't go far enough
-			 */
+	bch_btree_iter_init(b, &iter, from);
 
-			ret = submit_partial_cache_miss(b, op,
-					&KEY(KEY_INODE(&b->key),
-					     KEY_OFFSET(&b->key), 0));
-			break;
-		}
+	while ((k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad))) {
+		ret = !b->level
+			? fn(op, b, k)
+			: btree(map_keys_recurse, k, b, op, from, fn, flags);
+		from = NULL;
+
+		if (ret != MAP_CONTINUE)
+			return ret;
+	}
 
-		ret = b->level
-			? btree(search_recurse, k, b, op)
-			: submit_partial_cache_hit(b, op, k);
-	} while (!ret &&
-		 !op->lookup_done);
+	if (!b->level && (flags & MAP_END_KEY))
+		ret = fn(op, b, &KEY(KEY_INODE(&b->key),
+				     KEY_OFFSET(&b->key), 0));
 
 	return ret;
 }
 
+int bch_btree_map_keys(struct btree_op *op, struct cache_set *c,
+		       struct bkey *from, btree_map_keys_fn *fn, int flags)
+{
+	return btree_root(map_keys_recurse, c, op, from, fn, flags);
+}
+
 /* Keybuf code */
 
 static inline int keybuf_cmp(struct keybuf_key *l, struct keybuf_key *r)
@@ -2285,80 +2376,79 @@ static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
 	return clamp_t(int64_t, bkey_cmp(&l->key, &r->key), -1, 1);
 }
 
-static int bch_btree_refill_keybuf(struct btree *b, struct btree_op *op,
-				   struct keybuf *buf, struct bkey *end,
-				   keybuf_pred_fn *pred)
-{
-	struct btree_iter iter;
-	bch_btree_iter_init(b, &iter, &buf->last_scanned);
-
-	while (!array_freelist_empty(&buf->freelist)) {
-		struct bkey *k = bch_btree_iter_next_filter(&iter, b,
-							    bch_ptr_bad);
-
-		if (!b->level) {
-			if (!k) {
-				buf->last_scanned = b->key;
-				break;
-			}
+struct refill {
+	struct btree_op	op;
+	unsigned	nr_found;
+	struct keybuf	*buf;
+	struct bkey	*end;
+	keybuf_pred_fn	*pred;
+};
 
-			buf->last_scanned = *k;
-			if (bkey_cmp(&buf->last_scanned, end) >= 0)
-				break;
+static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
+			    struct bkey *k)
+{
+	struct refill *refill = container_of(op, struct refill, op);
+	struct keybuf *buf = refill->buf;
+	int ret = MAP_CONTINUE;
 
-			if (pred(buf, k)) {
-				struct keybuf_key *w;
+	if (bkey_cmp(k, refill->end) >= 0) {
+		ret = MAP_DONE;
+		goto out;
+	}
 
-				spin_lock(&buf->lock);
+	if (!KEY_SIZE(k)) /* end key */
+		goto out;
 
-				w = array_alloc(&buf->freelist);
+	if (refill->pred(buf, k)) {
+		struct keybuf_key *w;
 
-				w->private = NULL;
-				bkey_copy(&w->key, k);
+		spin_lock(&buf->lock);
 
-				if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
-					array_free(&buf->freelist, w);
+		w = array_alloc(&buf->freelist);
+		if (!w) {
+			spin_unlock(&buf->lock);
+			return MAP_DONE;
+		}
 
-				spin_unlock(&buf->lock);
-			}
-		} else {
-			if (!k)
-				break;
+		w->private = NULL;
+		bkey_copy(&w->key, k);
 
-			btree(refill_keybuf, k, b, op, buf, end, pred);
-			/*
-			 * Might get an error here, but can't really do anything
-			 * and it'll get logged elsewhere. Just read what we
-			 * can.
-			 */
+		if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
+			array_free(&buf->freelist, w);
+		else
+			refill->nr_found++;
 
-			if (bkey_cmp(&buf->last_scanned, end) >= 0)
-				break;
+		if (array_freelist_empty(&buf->freelist))
+			ret = MAP_DONE;
 
-			cond_resched();
-		}
+		spin_unlock(&buf->lock);
 	}
-
-	return 0;
+out:
+	buf->last_scanned = *k;
+	return ret;
 }
 
 void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
 		       struct bkey *end, keybuf_pred_fn *pred)
 {
 	struct bkey start = buf->last_scanned;
-	struct btree_op op;
-	bch_btree_op_init_stack(&op);
+	struct refill refill;
 
 	cond_resched();
 
-	btree_root(refill_keybuf, c, &op, buf, end, pred);
-	closure_sync(&op.cl);
+	bch_btree_op_init(&refill.op, -1);
+	refill.nr_found	= 0;
+	refill.buf	= buf;
+	refill.end	= end;
+	refill.pred	= pred;
+
+	bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
+			   refill_keybuf_fn, MAP_END_KEY);
 
-	pr_debug("found %s keys from %llu:%llu to %llu:%llu",
-		 RB_EMPTY_ROOT(&buf->keys) ? "no" :
-		 array_freelist_empty(&buf->freelist) ? "some" : "a few",
-		 KEY_INODE(&start), KEY_OFFSET(&start),
-		 KEY_INODE(&buf->last_scanned), KEY_OFFSET(&buf->last_scanned));
+	trace_bcache_keyscan(refill.nr_found,
+			     KEY_INODE(&start), KEY_OFFSET(&start),
+			     KEY_INODE(&buf->last_scanned),
+			     KEY_OFFSET(&buf->last_scanned));
 
 	spin_lock(&buf->lock);
 
@@ -2436,9 +2526,9 @@ struct keybuf_key *bch_keybuf_next(struct keybuf *buf)
 }
 
 struct keybuf_key *bch_keybuf_next_rescan(struct cache_set *c,
-					     struct keybuf *buf,
-					     struct bkey *end,
-					     keybuf_pred_fn *pred)
+					  struct keybuf *buf,
+					  struct bkey *end,
+					  keybuf_pred_fn *pred)
 {
 	struct keybuf_key *ret;
 
@@ -2471,14 +2561,12 @@ void bch_btree_exit(void)
 {
 	if (btree_io_wq)
 		destroy_workqueue(btree_io_wq);
-	if (bch_gc_wq)
-		destroy_workqueue(bch_gc_wq);
 }
 
 int __init bch_btree_init(void)
 {
-	if (!(bch_gc_wq = create_singlethread_workqueue("bch_btree_gc")) ||
-	    !(btree_io_wq = create_singlethread_workqueue("bch_btree_io")))
+	btree_io_wq = create_singlethread_workqueue("bch_btree_io");
+	if (!btree_io_wq)
 		return -ENOMEM;
 
 	return 0;
diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index 3333d3723633..767e75570896 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -125,6 +125,7 @@ struct btree {
 	unsigned long		seq;
 	struct rw_semaphore	lock;
 	struct cache_set	*c;
+	struct btree		*parent;
 
 	unsigned long		flags;
 	uint16_t		written;	/* would be nice to kill */
@@ -200,12 +201,7 @@ static inline bool bkey_written(struct btree *b, struct bkey *k)
 
 static inline void set_gc_sectors(struct cache_set *c)
 {
-	atomic_set(&c->sectors_to_gc, c->sb.bucket_size * c->nbuckets / 8);
-}
-
-static inline bool bch_ptr_invalid(struct btree *b, const struct bkey *k)
-{
-	return __bch_ptr_invalid(b->c, b->level, k);
+	atomic_set(&c->sectors_to_gc, c->sb.bucket_size * c->nbuckets / 16);
 }
 
 static inline struct bkey *bch_btree_iter_init(struct btree *b,
@@ -215,6 +211,16 @@ static inline struct bkey *bch_btree_iter_init(struct btree *b,
 	return __bch_btree_iter_init(b, iter, search, b->sets);
 }
 
+static inline bool bch_ptr_invalid(struct btree *b, const struct bkey *k)
+{
+	if (b->level)
+		return bch_btree_ptr_invalid(b->c, k);
+	else
+		return bch_extent_ptr_invalid(b->c, k);
+}
+
+void bkey_put(struct cache_set *c, struct bkey *k);
+
 /* Looping macros */
 
 #define for_each_cached_btree(b, c, iter)				\
@@ -234,51 +240,17 @@ static inline struct bkey *bch_btree_iter_init(struct btree *b,
 /* Recursing down the btree */
 
 struct btree_op {
-	struct closure		cl;
-	struct cache_set	*c;
-
-	/* Journal entry we have a refcount on */
-	atomic_t		*journal;
-
-	/* Bio to be inserted into the cache */
-	struct bio		*cache_bio;
-
-	unsigned		inode;
-
-	uint16_t		write_prio;
-
 	/* Btree level at which we start taking write locks */
 	short			lock;
 
-	/* Btree insertion type */
-	enum {
-		BTREE_INSERT,
-		BTREE_REPLACE
-	} type:8;
-
-	unsigned		csum:1;
-	unsigned		skip:1;
-	unsigned		flush_journal:1;
-
-	unsigned		insert_data_done:1;
-	unsigned		lookup_done:1;
 	unsigned		insert_collision:1;
-
-	/* Anything after this point won't get zeroed in do_bio_hook() */
-
-	/* Keys to be inserted */
-	struct keylist		keys;
-	BKEY_PADDED(replace);
 };
 
-enum {
-	BTREE_INSERT_STATUS_INSERT,
-	BTREE_INSERT_STATUS_BACK_MERGE,
-	BTREE_INSERT_STATUS_OVERWROTE,
-	BTREE_INSERT_STATUS_FRONT_MERGE,
-};
-
-void bch_btree_op_init_stack(struct btree_op *);
+static inline void bch_btree_op_init(struct btree_op *op, int write_lock_level)
+{
+	memset(op, 0, sizeof(struct btree_op));
+	op->lock = write_lock_level;
+}
 
 static inline void rw_lock(bool w, struct btree *b, int level)
 {
@@ -290,108 +262,71 @@ static inline void rw_lock(bool w, struct btree *b, int level)
 
 static inline void rw_unlock(bool w, struct btree *b)
 {
-#ifdef CONFIG_BCACHE_EDEBUG
-	unsigned i;
-
-	if (w && b->key.ptr[0])
-		for (i = 0; i <= b->nsets; i++)
-			bch_check_key_order(b, b->sets[i].data);
-#endif
-
 	if (w)
 		b->seq++;
 	(w ? up_write : up_read)(&b->lock);
 }
 
-#define insert_lock(s, b)	((b)->level <= (s)->lock)
+void bch_btree_node_read(struct btree *);
+void bch_btree_node_write(struct btree *, struct closure *);
 
-/*
- * These macros are for recursing down the btree - they handle the details of
- * locking and looking up nodes in the cache for you. They're best treated as
- * mere syntax when reading code that uses them.
- *
- * op->lock determines whether we take a read or a write lock at a given depth.
- * If you've got a read lock and find that you need a write lock (i.e. you're
- * going to have to split), set op->lock and return -EINTR; btree_root() will
- * call you again and you'll have the correct lock.
- */
+void bch_btree_set_root(struct btree *);
+struct btree *bch_btree_node_alloc(struct cache_set *, int, bool);
+struct btree *bch_btree_node_get(struct cache_set *, struct bkey *, int, bool);
 
-/**
- * btree - recurse down the btree on a specified key
- * @fn:		function to call, which will be passed the child node
- * @key:	key to recurse on
- * @b:		parent btree node
- * @op:		pointer to struct btree_op
- */
-#define btree(fn, key, b, op, ...)					\
-({									\
-	int _r, l = (b)->level - 1;					\
-	bool _w = l <= (op)->lock;					\
-	struct btree *_b = bch_btree_node_get((b)->c, key, l, op);	\
-	if (!IS_ERR(_b)) {						\
-		_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__);		\
-		rw_unlock(_w, _b);					\
-	} else								\
-		_r = PTR_ERR(_b);					\
-	_r;								\
-})
-
-/**
- * btree_root - call a function on the root of the btree
- * @fn:		function to call, which will be passed the child node
- * @c:		cache set
- * @op:		pointer to struct btree_op
- */
-#define btree_root(fn, c, op, ...)					\
-({									\
-	int _r = -EINTR;						\
-	do {								\
-		struct btree *_b = (c)->root;				\
-		bool _w = insert_lock(op, _b);				\
-		rw_lock(_w, _b, _b->level);				\
-		if (_b == (c)->root &&					\
-		    _w == insert_lock(op, _b))				\
-			_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__);	\
-		rw_unlock(_w, _b);					\
-		bch_cannibalize_unlock(c, &(op)->cl);		\
-	} while (_r == -EINTR);						\
-									\
-	_r;								\
-})
+int bch_btree_insert_check_key(struct btree *, struct btree_op *,
+			       struct bkey *);
+int bch_btree_insert(struct cache_set *, struct keylist *,
+		     atomic_t *, struct bkey *);
+
+int bch_gc_thread_start(struct cache_set *);
+size_t bch_btree_gc_finish(struct cache_set *);
+void bch_moving_gc(struct cache_set *);
+int bch_btree_check(struct cache_set *);
+uint8_t __bch_btree_mark_key(struct cache_set *, int, struct bkey *);
 
-static inline bool should_split(struct btree *b)
+static inline void wake_up_gc(struct cache_set *c)
 {
-	struct bset *i = write_block(b);
-	return b->written >= btree_blocks(b) ||
-		(i->seq == b->sets[0].data->seq &&
-		 b->written + __set_blocks(i, i->keys + 15, b->c)
-		 > btree_blocks(b));
+	if (c->gc_thread)
+		wake_up_process(c->gc_thread);
 }
 
-void bch_btree_node_read(struct btree *);
-void bch_btree_node_write(struct btree *, struct closure *);
+#define MAP_DONE	0
+#define MAP_CONTINUE	1
 
-void bch_cannibalize_unlock(struct cache_set *, struct closure *);
-void bch_btree_set_root(struct btree *);
-struct btree *bch_btree_node_alloc(struct cache_set *, int, struct closure *);
-struct btree *bch_btree_node_get(struct cache_set *, struct bkey *,
-				int, struct btree_op *);
+#define MAP_ALL_NODES	0
+#define MAP_LEAF_NODES	1
 
-bool bch_btree_insert_check_key(struct btree *, struct btree_op *,
-				   struct bio *);
-int bch_btree_insert(struct btree_op *, struct cache_set *);
+#define MAP_END_KEY	1
 
-int bch_btree_search_recurse(struct btree *, struct btree_op *);
+typedef int (btree_map_nodes_fn)(struct btree_op *, struct btree *);
+int __bch_btree_map_nodes(struct btree_op *, struct cache_set *,
+			  struct bkey *, btree_map_nodes_fn *, int);
 
-void bch_queue_gc(struct cache_set *);
-size_t bch_btree_gc_finish(struct cache_set *);
-void bch_moving_gc(struct closure *);
-int bch_btree_check(struct cache_set *, struct btree_op *);
-uint8_t __bch_btree_mark_key(struct cache_set *, int, struct bkey *);
+static inline int bch_btree_map_nodes(struct btree_op *op, struct cache_set *c,
+				      struct bkey *from, btree_map_nodes_fn *fn)
+{
+	return __bch_btree_map_nodes(op, c, from, fn, MAP_ALL_NODES);
+}
+
+static inline int bch_btree_map_leaf_nodes(struct btree_op *op,
+					   struct cache_set *c,
+					   struct bkey *from,
+					   btree_map_nodes_fn *fn)
+{
+	return __bch_btree_map_nodes(op, c, from, fn, MAP_LEAF_NODES);
+}
+
+typedef int (btree_map_keys_fn)(struct btree_op *, struct btree *,
+				struct bkey *);
+int bch_btree_map_keys(struct btree_op *, struct cache_set *,
+		       struct bkey *, btree_map_keys_fn *, int);
+
+typedef bool (keybuf_pred_fn)(struct keybuf *, struct bkey *);
 
 void bch_keybuf_init(struct keybuf *);
-void bch_refill_keybuf(struct cache_set *, struct keybuf *, struct bkey *,
-		       keybuf_pred_fn *);
+void bch_refill_keybuf(struct cache_set *, struct keybuf *,
+		       struct bkey *, keybuf_pred_fn *);
 bool bch_keybuf_check_overlapping(struct keybuf *, struct bkey *,
 				  struct bkey *);
 void bch_keybuf_del(struct keybuf *, struct keybuf_key *);
diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
index 9aba2017f0d1..dfff2410322e 100644
--- a/drivers/md/bcache/closure.c
+++ b/drivers/md/bcache/closure.c
@@ -11,17 +11,6 @@
 
 #include "closure.h"
 
-void closure_queue(struct closure *cl)
-{
-	struct workqueue_struct *wq = cl->wq;
-	if (wq) {
-		INIT_WORK(&cl->work, cl->work.func);
-		BUG_ON(!queue_work(wq, &cl->work));
-	} else
-		cl->fn(cl);
-}
-EXPORT_SYMBOL_GPL(closure_queue);
-
 #define CL_FIELD(type, field)					\
 	case TYPE_ ## type:					\
 	return &container_of(cl, struct type, cl)->field
@@ -30,17 +19,6 @@ static struct closure_waitlist *closure_waitlist(struct closure *cl)
 {
 	switch (cl->type) {
 		CL_FIELD(closure_with_waitlist, wait);
-		CL_FIELD(closure_with_waitlist_and_timer, wait);
-	default:
-		return NULL;
-	}
-}
-
-static struct timer_list *closure_timer(struct closure *cl)
-{
-	switch (cl->type) {
-		CL_FIELD(closure_with_timer, timer);
-		CL_FIELD(closure_with_waitlist_and_timer, timer);
 	default:
 		return NULL;
 	}
@@ -51,7 +29,7 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
 	int r = flags & CLOSURE_REMAINING_MASK;
 
 	BUG_ON(flags & CLOSURE_GUARD_MASK);
-	BUG_ON(!r && (flags & ~(CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING)));
+	BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
 
 	/* Must deliver precisely one wakeup */
 	if (r == 1 && (flags & CLOSURE_SLEEPING))
@@ -59,7 +37,6 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
 
 	if (!r) {
 		if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
-			/* CLOSURE_BLOCKING might be set - clear it */
 			atomic_set(&cl->remaining,
 				   CLOSURE_REMAINING_INITIALIZER);
 			closure_queue(cl);
@@ -90,13 +67,13 @@ void closure_sub(struct closure *cl, int v)
 {
 	closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining));
 }
-EXPORT_SYMBOL_GPL(closure_sub);
+EXPORT_SYMBOL(closure_sub);
 
 void closure_put(struct closure *cl)
 {
 	closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
 }
-EXPORT_SYMBOL_GPL(closure_put);
+EXPORT_SYMBOL(closure_put);
 
 static void set_waiting(struct closure *cl, unsigned long f)
 {
@@ -133,7 +110,7 @@ void __closure_wake_up(struct closure_waitlist *wait_list)
 		closure_sub(cl, CLOSURE_WAITING + 1);
 	}
 }
-EXPORT_SYMBOL_GPL(__closure_wake_up);
+EXPORT_SYMBOL(__closure_wake_up);
 
 bool closure_wait(struct closure_waitlist *list, struct closure *cl)
 {
@@ -146,7 +123,7 @@ bool closure_wait(struct closure_waitlist *list, struct closure *cl)
 
 	return true;
 }
-EXPORT_SYMBOL_GPL(closure_wait);
+EXPORT_SYMBOL(closure_wait);
 
 /**
  * closure_sync() - sleep until a closure a closure has nothing left to wait on
@@ -169,7 +146,7 @@ void closure_sync(struct closure *cl)
 
 	__closure_end_sleep(cl);
 }
-EXPORT_SYMBOL_GPL(closure_sync);
+EXPORT_SYMBOL(closure_sync);
 
 /**
  * closure_trylock() - try to acquire the closure, without waiting
@@ -183,17 +160,17 @@ bool closure_trylock(struct closure *cl, struct closure *parent)
 			   CLOSURE_REMAINING_INITIALIZER) != -1)
 		return false;
 
-	closure_set_ret_ip(cl);
-
 	smp_mb();
+
 	cl->parent = parent;
 	if (parent)
 		closure_get(parent);
 
+	closure_set_ret_ip(cl);
 	closure_debug_create(cl);
 	return true;
 }
-EXPORT_SYMBOL_GPL(closure_trylock);
+EXPORT_SYMBOL(closure_trylock);
 
 void __closure_lock(struct closure *cl, struct closure *parent,
 		    struct closure_waitlist *wait_list)
@@ -205,57 +182,11 @@ void __closure_lock(struct closure *cl, struct closure *parent,
 		if (closure_trylock(cl, parent))
 			return;
 
-		closure_wait_event_sync(wait_list, &wait,
-					atomic_read(&cl->remaining) == -1);
+		closure_wait_event(wait_list, &wait,
+				   atomic_read(&cl->remaining) == -1);
 	}
 }
-EXPORT_SYMBOL_GPL(__closure_lock);
-
-static void closure_delay_timer_fn(unsigned long data)
-{
-	struct closure *cl = (struct closure *) data;
-	closure_sub(cl, CLOSURE_TIMER + 1);
-}
-
-void do_closure_timer_init(struct closure *cl)
-{
-	struct timer_list *timer = closure_timer(cl);
-
-	init_timer(timer);
-	timer->data	= (unsigned long) cl;
-	timer->function = closure_delay_timer_fn;
-}
-EXPORT_SYMBOL_GPL(do_closure_timer_init);
-
-bool __closure_delay(struct closure *cl, unsigned long delay,
-		     struct timer_list *timer)
-{
-	if (atomic_read(&cl->remaining) & CLOSURE_TIMER)
-		return false;
-
-	BUG_ON(timer_pending(timer));
-
-	timer->expires	= jiffies + delay;
-
-	atomic_add(CLOSURE_TIMER + 1, &cl->remaining);
-	add_timer(timer);
-	return true;
-}
-EXPORT_SYMBOL_GPL(__closure_delay);
-
-void __closure_flush(struct closure *cl, struct timer_list *timer)
-{
-	if (del_timer(timer))
-		closure_sub(cl, CLOSURE_TIMER + 1);
-}
-EXPORT_SYMBOL_GPL(__closure_flush);
-
-void __closure_flush_sync(struct closure *cl, struct timer_list *timer)
-{
-	if (del_timer_sync(timer))
-		closure_sub(cl, CLOSURE_TIMER + 1);
-}
-EXPORT_SYMBOL_GPL(__closure_flush_sync);
+EXPORT_SYMBOL(__closure_lock);
 
 #ifdef CONFIG_BCACHE_CLOSURES_DEBUG
 
@@ -273,7 +204,7 @@ void closure_debug_create(struct closure *cl)
 	list_add(&cl->all, &closure_list);
 	spin_unlock_irqrestore(&closure_list_lock, flags);
 }
-EXPORT_SYMBOL_GPL(closure_debug_create);
+EXPORT_SYMBOL(closure_debug_create);
 
 void closure_debug_destroy(struct closure *cl)
 {
@@ -286,7 +217,7 @@ void closure_debug_destroy(struct closure *cl)
 	list_del(&cl->all);
 	spin_unlock_irqrestore(&closure_list_lock, flags);
 }
-EXPORT_SYMBOL_GPL(closure_debug_destroy);
+EXPORT_SYMBOL(closure_debug_destroy);
 
 static struct dentry *debug;
 
@@ -304,14 +235,12 @@ static int debug_seq_show(struct seq_file *f, void *data)
 			   cl, (void *) cl->ip, cl->fn, cl->parent,
 			   r & CLOSURE_REMAINING_MASK);
 
-		seq_printf(f, "%s%s%s%s%s%s\n",
+		seq_printf(f, "%s%s%s%s\n",
 			   test_bit(WORK_STRUCT_PENDING,
 				    work_data_bits(&cl->work)) ? "Q" : "",
 			   r & CLOSURE_RUNNING	? "R" : "",
-			   r & CLOSURE_BLOCKING	? "B" : "",
 			   r & CLOSURE_STACK	? "S" : "",
-			   r & CLOSURE_SLEEPING	? "Sl" : "",
-			   r & CLOSURE_TIMER	? "T" : "");
+			   r & CLOSURE_SLEEPING	? "Sl" : "");
 
 		if (r & CLOSURE_WAITING)
 			seq_printf(f, " W %pF\n",
diff --git a/drivers/md/bcache/closure.h b/drivers/md/bcache/closure.h
index 00039924ea9d..9762f1be3304 100644
--- a/drivers/md/bcache/closure.h
+++ b/drivers/md/bcache/closure.h
@@ -155,21 +155,6 @@
  * delayed_work embeds a work item and a timer_list. The important thing is, use
  * it exactly like you would a regular closure and closure_put() will magically
  * handle everything for you.
- *
- * We've got closures that embed timers, too. They're called, appropriately
- * enough:
- * struct closure_with_timer;
- *
- * This gives you access to closure_delay(). It takes a refcount for a specified
- * number of jiffies - you could then call closure_sync() (for a slightly
- * convoluted version of msleep()) or continue_at() - which gives you the same
- * effect as using a delayed work item, except you can reuse the work_struct
- * already embedded in struct closure.
- *
- * Lastly, there's struct closure_with_waitlist_and_timer. It does what you
- * probably expect, if you happen to need the features of both. (You don't
- * really want to know how all this is implemented, but if I've done my job
- * right you shouldn't have to care).
  */
 
 struct closure;
@@ -182,16 +167,11 @@ struct closure_waitlist {
 enum closure_type {
 	TYPE_closure				= 0,
 	TYPE_closure_with_waitlist		= 1,
-	TYPE_closure_with_timer			= 2,
-	TYPE_closure_with_waitlist_and_timer	= 3,
-	MAX_CLOSURE_TYPE			= 3,
+	MAX_CLOSURE_TYPE			= 1,
 };
 
 enum closure_state {
 	/*
-	 * CLOSURE_BLOCKING: Causes closure_wait_event() to block, instead of
-	 * waiting asynchronously
-	 *
 	 * CLOSURE_WAITING: Set iff the closure is on a waitlist. Must be set by
 	 * the thread that owns the closure, and cleared by the thread that's
 	 * waking up the closure.
@@ -200,10 +180,6 @@ enum closure_state {
 	 * - indicates that cl->task is valid and closure_put() may wake it up.
 	 * Only set or cleared by the thread that owns the closure.
 	 *
-	 * CLOSURE_TIMER: Analagous to CLOSURE_WAITING, indicates that a closure
-	 * has an outstanding timer. Must be set by the thread that owns the
-	 * closure, and cleared by the timer function when the timer goes off.
-	 *
 	 * The rest are for debugging and don't affect behaviour:
 	 *
 	 * CLOSURE_RUNNING: Set when a closure is running (i.e. by
@@ -218,19 +194,17 @@ enum closure_state {
 	 * closure with this flag set
 	 */
 
-	CLOSURE_BITS_START	= (1 << 19),
-	CLOSURE_DESTRUCTOR	= (1 << 19),
-	CLOSURE_BLOCKING	= (1 << 21),
-	CLOSURE_WAITING		= (1 << 23),
-	CLOSURE_SLEEPING	= (1 << 25),
-	CLOSURE_TIMER		= (1 << 27),
+	CLOSURE_BITS_START	= (1 << 23),
+	CLOSURE_DESTRUCTOR	= (1 << 23),
+	CLOSURE_WAITING		= (1 << 25),
+	CLOSURE_SLEEPING	= (1 << 27),
 	CLOSURE_RUNNING		= (1 << 29),
 	CLOSURE_STACK		= (1 << 31),
 };
 
 #define CLOSURE_GUARD_MASK					\
-	((CLOSURE_DESTRUCTOR|CLOSURE_BLOCKING|CLOSURE_WAITING|	\
-	  CLOSURE_SLEEPING|CLOSURE_TIMER|CLOSURE_RUNNING|CLOSURE_STACK) << 1)
+	((CLOSURE_DESTRUCTOR|CLOSURE_WAITING|CLOSURE_SLEEPING|	\
+	  CLOSURE_RUNNING|CLOSURE_STACK) << 1)
 
 #define CLOSURE_REMAINING_MASK		(CLOSURE_BITS_START - 1)
 #define CLOSURE_REMAINING_INITIALIZER	(1|CLOSURE_RUNNING)
@@ -268,17 +242,6 @@ struct closure_with_waitlist {
 	struct closure_waitlist	wait;
 };
 
-struct closure_with_timer {
-	struct closure		cl;
-	struct timer_list	timer;
-};
-
-struct closure_with_waitlist_and_timer {
-	struct closure		cl;
-	struct closure_waitlist	wait;
-	struct timer_list	timer;
-};
-
 extern unsigned invalid_closure_type(void);
 
 #define __CLOSURE_TYPE(cl, _t)						\
@@ -289,14 +252,11 @@ extern unsigned invalid_closure_type(void);
 (									\
 	__CLOSURE_TYPE(cl, closure)					\
 	__CLOSURE_TYPE(cl, closure_with_waitlist)			\
-	__CLOSURE_TYPE(cl, closure_with_timer)				\
-	__CLOSURE_TYPE(cl, closure_with_waitlist_and_timer)		\
 	invalid_closure_type()						\
 )
 
 void closure_sub(struct closure *cl, int v);
 void closure_put(struct closure *cl);
-void closure_queue(struct closure *cl);
 void __closure_wake_up(struct closure_waitlist *list);
 bool closure_wait(struct closure_waitlist *list, struct closure *cl);
 void closure_sync(struct closure *cl);
@@ -305,12 +265,6 @@ bool closure_trylock(struct closure *cl, struct closure *parent);
 void __closure_lock(struct closure *cl, struct closure *parent,
 		    struct closure_waitlist *wait_list);
 
-void do_closure_timer_init(struct closure *cl);
-bool __closure_delay(struct closure *cl, unsigned long delay,
-		     struct timer_list *timer);
-void __closure_flush(struct closure *cl, struct timer_list *timer);
-void __closure_flush_sync(struct closure *cl, struct timer_list *timer);
-
 #ifdef CONFIG_BCACHE_CLOSURES_DEBUG
 
 void closure_debug_init(void);
@@ -354,11 +308,6 @@ static inline void closure_set_stopped(struct closure *cl)
 	atomic_sub(CLOSURE_RUNNING, &cl->remaining);
 }
 
-static inline bool closure_is_stopped(struct closure *cl)
-{
-	return !(atomic_read(&cl->remaining) & CLOSURE_RUNNING);
-}
-
 static inline bool closure_is_unlocked(struct closure *cl)
 {
 	return atomic_read(&cl->remaining) == -1;
@@ -367,14 +316,6 @@ static inline bool closure_is_unlocked(struct closure *cl)
 static inline void do_closure_init(struct closure *cl, struct closure *parent,
 				   bool running)
 {
-	switch (cl->type) {
-	case TYPE_closure_with_timer:
-	case TYPE_closure_with_waitlist_and_timer:
-		do_closure_timer_init(cl);
-	default:
-		break;
-	}
-
 	cl->parent = parent;
 	if (parent)
 		closure_get(parent);
@@ -429,8 +370,7 @@ do {								\
 static inline void closure_init_stack(struct closure *cl)
 {
 	memset(cl, 0, sizeof(struct closure));
-	atomic_set(&cl->remaining, CLOSURE_REMAINING_INITIALIZER|
-		   CLOSURE_BLOCKING|CLOSURE_STACK);
+	atomic_set(&cl->remaining, CLOSURE_REMAINING_INITIALIZER|CLOSURE_STACK);
 }
 
 /**
@@ -461,24 +401,6 @@ do {								\
 #define closure_lock(cl, parent)				\
 	__closure_lock(__to_internal_closure(cl), parent, &(cl)->wait)
 
-/**
- * closure_delay() - delay some number of jiffies
- * @cl:		the closure that will sleep
- * @delay:	the delay in jiffies
- *
- * Takes a refcount on @cl which will be released after @delay jiffies; this may
- * be used to have a function run after a delay with continue_at(), or
- * closure_sync() may be used for a convoluted version of msleep().
- */
-#define closure_delay(cl, delay)			\
-	__closure_delay(__to_internal_closure(cl), delay, &(cl)->timer)
-
-#define closure_flush(cl)				\
-	__closure_flush(__to_internal_closure(cl), &(cl)->timer)
-
-#define closure_flush_sync(cl)				\
-	__closure_flush_sync(__to_internal_closure(cl), &(cl)->timer)
-
 static inline void __closure_end_sleep(struct closure *cl)
 {
 	__set_current_state(TASK_RUNNING);
@@ -498,40 +420,6 @@ static inline void __closure_start_sleep(struct closure *cl)
 }
 
 /**
- * closure_blocking() - returns true if the closure is in blocking mode.
- *
- * If a closure is in blocking mode, closure_wait_event() will sleep until the
- * condition is true instead of waiting asynchronously.
- */
-static inline bool closure_blocking(struct closure *cl)
-{
-	return atomic_read(&cl->remaining) & CLOSURE_BLOCKING;
-}
-
-/**
- * set_closure_blocking() - put a closure in blocking mode.
- *
- * If a closure is in blocking mode, closure_wait_event() will sleep until the
- * condition is true instead of waiting asynchronously.
- *
- * Not thread safe - can only be called by the thread running the closure.
- */
-static inline void set_closure_blocking(struct closure *cl)
-{
-	if (!closure_blocking(cl))
-		atomic_add(CLOSURE_BLOCKING, &cl->remaining);
-}
-
-/*
- * Not thread safe - can only be called by the thread running the closure.
- */
-static inline void clear_closure_blocking(struct closure *cl)
-{
-	if (closure_blocking(cl))
-		atomic_sub(CLOSURE_BLOCKING, &cl->remaining);
-}
-
-/**
  * closure_wake_up() - wake up all closures on a wait list.
  */
 static inline void closure_wake_up(struct closure_waitlist *list)
@@ -561,63 +449,36 @@ static inline void closure_wake_up(struct closure_waitlist *list)
  * refcount on our closure. If this was a stack allocated closure, that would be
  * bad.
  */
-#define __closure_wait_event(list, cl, condition, _block)		\
+#define closure_wait_event(list, cl, condition)				\
 ({									\
-	bool block = _block;						\
 	typeof(condition) ret;						\
 									\
 	while (1) {							\
 		ret = (condition);					\
 		if (ret) {						\
 			__closure_wake_up(list);			\
-			if (block)					\
-				closure_sync(cl);			\
-									\
+			closure_sync(cl);				\
 			break;						\
 		}							\
 									\
-		if (block)						\
-			__closure_start_sleep(cl);			\
-									\
-		if (!closure_wait(list, cl)) {				\
-			if (!block)					\
-				break;					\
+		__closure_start_sleep(cl);				\
 									\
+		if (!closure_wait(list, cl))				\
 			schedule();					\
-		}							\
 	}								\
 									\
 	ret;								\
 })
 
-/**
- * closure_wait_event() - wait on a condition, synchronously or asynchronously.
- * @list:	the wait list to wait on
- * @cl:		the closure that is doing the waiting
- * @condition:	a C expression for the event to wait for
- *
- * If the closure is in blocking mode, sleeps until the @condition evaluates to
- * true - exactly like wait_event().
- *
- * If the closure is not in blocking mode, waits asynchronously; if the
- * condition is currently false the @cl is put onto @list and returns. @list
- * owns a refcount on @cl; closure_sync() or continue_at() may be used later to
- * wait for another thread to wake up @list, which drops the refcount on @cl.
- *
- * Returns the value of @condition; @cl will be on @list iff @condition was
- * false.
- *
- * closure_wake_up(@list) must be called after changing any variable that could
- * cause @condition to become true.
- */
-#define closure_wait_event(list, cl, condition)				\
-	__closure_wait_event(list, cl, condition, closure_blocking(cl))
-
-#define closure_wait_event_async(list, cl, condition)			\
-	__closure_wait_event(list, cl, condition, false)
-
-#define closure_wait_event_sync(list, cl, condition)			\
-	__closure_wait_event(list, cl, condition, true)
+static inline void closure_queue(struct closure *cl)
+{
+	struct workqueue_struct *wq = cl->wq;
+	if (wq) {
+		INIT_WORK(&cl->work, cl->work.func);
+		BUG_ON(!queue_work(wq, &cl->work));
+	} else
+		cl->fn(cl);
+}
 
 static inline void set_closure_fn(struct closure *cl, closure_fn *fn,
 				  struct workqueue_struct *wq)
@@ -642,7 +503,7 @@ do {									\
 #define continue_at_nobarrier(_cl, _fn, _wq)				\
 do {									\
 	set_closure_fn(_cl, _fn, _wq);					\
-	closure_queue(cl);						\
+	closure_queue(_cl);						\
 	return;								\
 } while (0)
 
diff --git a/drivers/md/bcache/debug.c b/drivers/md/bcache/debug.c
index 88e6411eab4f..264fcfbd6290 100644
--- a/drivers/md/bcache/debug.c
+++ b/drivers/md/bcache/debug.c
@@ -8,7 +8,6 @@
 #include "bcache.h"
 #include "btree.h"
 #include "debug.h"
-#include "request.h"
 
 #include <linux/console.h>
 #include <linux/debugfs.h>
@@ -77,29 +76,17 @@ int bch_bkey_to_text(char *buf, size_t size, const struct bkey *k)
 	return out - buf;
 }
 
-int bch_btree_to_text(char *buf, size_t size, const struct btree *b)
-{
-	return scnprintf(buf, size, "%zu level %i/%i",
-			 PTR_BUCKET_NR(b->c, &b->key, 0),
-			 b->level, b->c->root ? b->c->root->level : -1);
-}
-
-#if defined(CONFIG_BCACHE_DEBUG) || defined(CONFIG_BCACHE_EDEBUG)
-
-static bool skipped_backwards(struct btree *b, struct bkey *k)
-{
-	return bkey_cmp(k, (!b->level)
-			? &START_KEY(bkey_next(k))
-			: bkey_next(k)) > 0;
-}
+#ifdef CONFIG_BCACHE_DEBUG
 
 static void dump_bset(struct btree *b, struct bset *i)
 {
-	struct bkey *k;
+	struct bkey *k, *next;
 	unsigned j;
 	char buf[80];
 
-	for (k = i->start; k < end(i); k = bkey_next(k)) {
+	for (k = i->start; k < end(i); k = next) {
+		next = bkey_next(k);
+
 		bch_bkey_to_text(buf, sizeof(buf), k);
 		printk(KERN_ERR "block %zu key %zi/%u: %s", index(i, b),
 		       (uint64_t *) k - i->d, i->keys, buf);
@@ -115,15 +102,21 @@ static void dump_bset(struct btree *b, struct bset *i)
 
 		printk(" %s\n", bch_ptr_status(b->c, k));
 
-		if (bkey_next(k) < end(i) &&
-		    skipped_backwards(b, k))
+		if (next < end(i) &&
+		    bkey_cmp(k, !b->level ? &START_KEY(next) : next) > 0)
 			printk(KERN_ERR "Key skipped backwards\n");
 	}
 }
 
-#endif
+static void bch_dump_bucket(struct btree *b)
+{
+	unsigned i;
 
-#ifdef CONFIG_BCACHE_DEBUG
+	console_lock();
+	for (i = 0; i <= b->nsets; i++)
+		dump_bset(b, b->sets[i].data);
+	console_unlock();
+}
 
 void bch_btree_verify(struct btree *b, struct bset *new)
 {
@@ -176,66 +169,44 @@ void bch_btree_verify(struct btree *b, struct bset *new)
 	mutex_unlock(&b->c->verify_lock);
 }
 
-static void data_verify_endio(struct bio *bio, int error)
-{
-	struct closure *cl = bio->bi_private;
-	closure_put(cl);
-}
-
-void bch_data_verify(struct search *s)
+void bch_data_verify(struct cached_dev *dc, struct bio *bio)
 {
 	char name[BDEVNAME_SIZE];
-	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
-	struct closure *cl = &s->cl;
 	struct bio *check;
 	struct bio_vec *bv;
 	int i;
 
-	if (!s->unaligned_bvec)
-		bio_for_each_segment(bv, s->orig_bio, i)
-			bv->bv_offset = 0, bv->bv_len = PAGE_SIZE;
-
-	check = bio_clone(s->orig_bio, GFP_NOIO);
+	check = bio_clone(bio, GFP_NOIO);
 	if (!check)
 		return;
 
 	if (bio_alloc_pages(check, GFP_NOIO))
 		goto out_put;
 
-	check->bi_rw		= READ_SYNC;
-	check->bi_private	= cl;
-	check->bi_end_io	= data_verify_endio;
-
-	closure_bio_submit(check, cl, &dc->disk);
-	closure_sync(cl);
+	submit_bio_wait(READ_SYNC, check);
 
-	bio_for_each_segment(bv, s->orig_bio, i) {
-		void *p1 = kmap(bv->bv_page);
-		void *p2 = kmap(check->bi_io_vec[i].bv_page);
+	bio_for_each_segment(bv, bio, i) {
+		void *p1 = kmap_atomic(bv->bv_page);
+		void *p2 = page_address(check->bi_io_vec[i].bv_page);
 
-		if (memcmp(p1 + bv->bv_offset,
-			   p2 + bv->bv_offset,
-			   bv->bv_len))
-			printk(KERN_ERR
-			       "bcache (%s): verify failed at sector %llu\n",
-			       bdevname(dc->bdev, name),
-			       (uint64_t) s->orig_bio->bi_sector);
+		cache_set_err_on(memcmp(p1 + bv->bv_offset,
+					p2 + bv->bv_offset,
+					bv->bv_len),
+				 dc->disk.c,
+				 "verify failed at dev %s sector %llu",
+				 bdevname(dc->bdev, name),
+				 (uint64_t) bio->bi_sector);
 
-		kunmap(bv->bv_page);
-		kunmap(check->bi_io_vec[i].bv_page);
+		kunmap_atomic(p1);
 	}
 
-	__bio_for_each_segment(bv, check, i, 0)
+	bio_for_each_segment_all(bv, check, i)
 		__free_page(bv->bv_page);
 out_put:
 	bio_put(check);
 }
 
-#endif
-
-#ifdef CONFIG_BCACHE_EDEBUG
-
-unsigned bch_count_data(struct btree *b)
+int __bch_count_data(struct btree *b)
 {
 	unsigned ret = 0;
 	struct btree_iter iter;
@@ -247,72 +218,60 @@ unsigned bch_count_data(struct btree *b)
 	return ret;
 }
 
-static void vdump_bucket_and_panic(struct btree *b, const char *fmt,
-				   va_list args)
-{
-	unsigned i;
-	char buf[80];
-
-	console_lock();
-
-	for (i = 0; i <= b->nsets; i++)
-		dump_bset(b, b->sets[i].data);
-
-	vprintk(fmt, args);
-
-	console_unlock();
-
-	bch_btree_to_text(buf, sizeof(buf), b);
-	panic("at %s\n", buf);
-}
-
-void bch_check_key_order_msg(struct btree *b, struct bset *i,
-			     const char *fmt, ...)
-{
-	struct bkey *k;
-
-	if (!i->keys)
-		return;
-
-	for (k = i->start; bkey_next(k) < end(i); k = bkey_next(k))
-		if (skipped_backwards(b, k)) {
-			va_list args;
-			va_start(args, fmt);
-
-			vdump_bucket_and_panic(b, fmt, args);
-			va_end(args);
-		}
-}
-
-void bch_check_keys(struct btree *b, const char *fmt, ...)
+void __bch_check_keys(struct btree *b, const char *fmt, ...)
 {
 	va_list args;
 	struct bkey *k, *p = NULL;
 	struct btree_iter iter;
-
-	if (b->level)
-		return;
+	const char *err;
 
 	for_each_key(b, k, &iter) {
-		if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0) {
-			printk(KERN_ERR "Keys out of order:\n");
-			goto bug;
-		}
-
-		if (bch_ptr_invalid(b, k))
-			continue;
-
-		if (p && bkey_cmp(p, &START_KEY(k)) > 0) {
-			printk(KERN_ERR "Overlapping keys:\n");
-			goto bug;
+		if (!b->level) {
+			err = "Keys out of order";
+			if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
+				goto bug;
+
+			if (bch_ptr_invalid(b, k))
+				continue;
+
+			err =  "Overlapping keys";
+			if (p && bkey_cmp(p, &START_KEY(k)) > 0)
+				goto bug;
+		} else {
+			if (bch_ptr_bad(b, k))
+				continue;
+
+			err = "Duplicate keys";
+			if (p && !bkey_cmp(p, k))
+				goto bug;
 		}
 		p = k;
 	}
+
+	err = "Key larger than btree node key";
+	if (p && bkey_cmp(p, &b->key) > 0)
+		goto bug;
+
 	return;
 bug:
+	bch_dump_bucket(b);
+
 	va_start(args, fmt);
-	vdump_bucket_and_panic(b, fmt, args);
+	vprintk(fmt, args);
 	va_end(args);
+
+	panic("bcache error: %s:\n", err);
+}
+
+void bch_btree_iter_next_check(struct btree_iter *iter)
+{
+	struct bkey *k = iter->data->k, *next = bkey_next(k);
+
+	if (next < iter->data->end &&
+	    bkey_cmp(k, iter->b->level ? next : &START_KEY(next)) > 0) {
+		bch_dump_bucket(iter->b);
+		panic("Key skipped backwards\n");
+	}
 }
 
 #endif
diff --git a/drivers/md/bcache/debug.h b/drivers/md/bcache/debug.h
index 1c39b5a2489b..2ede60e31874 100644
--- a/drivers/md/bcache/debug.h
+++ b/drivers/md/bcache/debug.h
@@ -4,40 +4,44 @@
 /* Btree/bkey debug printing */
 
 int bch_bkey_to_text(char *buf, size_t size, const struct bkey *k);
-int bch_btree_to_text(char *buf, size_t size, const struct btree *b);
-
-#ifdef CONFIG_BCACHE_EDEBUG
-
-unsigned bch_count_data(struct btree *);
-void bch_check_key_order_msg(struct btree *, struct bset *, const char *, ...);
-void bch_check_keys(struct btree *, const char *, ...);
-
-#define bch_check_key_order(b, i)			\
-	bch_check_key_order_msg(b, i, "keys out of order")
-#define EBUG_ON(cond)		BUG_ON(cond)
-
-#else /* EDEBUG */
-
-#define bch_count_data(b)				0
-#define bch_check_key_order(b, i)			do {} while (0)
-#define bch_check_key_order_msg(b, i, ...)		do {} while (0)
-#define bch_check_keys(b, ...)				do {} while (0)
-#define EBUG_ON(cond)					do {} while (0)
-
-#endif
 
 #ifdef CONFIG_BCACHE_DEBUG
 
 void bch_btree_verify(struct btree *, struct bset *);
-void bch_data_verify(struct search *);
+void bch_data_verify(struct cached_dev *, struct bio *);
+int __bch_count_data(struct btree *);
+void __bch_check_keys(struct btree *, const char *, ...);
+void bch_btree_iter_next_check(struct btree_iter *);
+
+#define EBUG_ON(cond)			BUG_ON(cond)
+#define expensive_debug_checks(c)	((c)->expensive_debug_checks)
+#define key_merging_disabled(c)		((c)->key_merging_disabled)
+#define bypass_torture_test(d)		((d)->bypass_torture_test)
 
 #else /* DEBUG */
 
 static inline void bch_btree_verify(struct btree *b, struct bset *i) {}
-static inline void bch_data_verify(struct search *s) {};
+static inline void bch_data_verify(struct cached_dev *dc, struct bio *bio) {}
+static inline int __bch_count_data(struct btree *b) { return -1; }
+static inline void __bch_check_keys(struct btree *b, const char *fmt, ...) {}
+static inline void bch_btree_iter_next_check(struct btree_iter *iter) {}
+
+#define EBUG_ON(cond)			do { if (cond); } while (0)
+#define expensive_debug_checks(c)	0
+#define key_merging_disabled(c)		0
+#define bypass_torture_test(d)		0
 
 #endif
 
+#define bch_count_data(b)						\
+	(expensive_debug_checks((b)->c) ? __bch_count_data(b) : -1)
+
+#define bch_check_keys(b, ...)						\
+do {									\
+	if (expensive_debug_checks((b)->c))				\
+		__bch_check_keys(b, __VA_ARGS__);			\
+} while (0)
+
 #ifdef CONFIG_DEBUG_FS
 void bch_debug_init_cache_set(struct cache_set *);
 #else
diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index 8435f81e5d85..ecdaa671bd50 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -7,7 +7,6 @@
 #include "bcache.h"
 #include "btree.h"
 #include "debug.h"
-#include "request.h"
 
 #include <trace/events/bcache.h>
 
@@ -31,17 +30,20 @@ static void journal_read_endio(struct bio *bio, int error)
 }
 
 static int journal_read_bucket(struct cache *ca, struct list_head *list,
-			       struct btree_op *op, unsigned bucket_index)
+			       unsigned bucket_index)
 {
 	struct journal_device *ja = &ca->journal;
 	struct bio *bio = &ja->bio;
 
 	struct journal_replay *i;
 	struct jset *j, *data = ca->set->journal.w[0].data;
+	struct closure cl;
 	unsigned len, left, offset = 0;
 	int ret = 0;
 	sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bucket_index]);
 
+	closure_init_stack(&cl);
+
 	pr_debug("reading %llu", (uint64_t) bucket);
 
 	while (offset < ca->sb.bucket_size) {
@@ -55,11 +57,11 @@ reread:		left = ca->sb.bucket_size - offset;
 		bio->bi_size	= len << 9;
 
 		bio->bi_end_io	= journal_read_endio;
-		bio->bi_private = &op->cl;
+		bio->bi_private = &cl;
 		bch_bio_map(bio, data);
 
-		closure_bio_submit(bio, &op->cl, ca);
-		closure_sync(&op->cl);
+		closure_bio_submit(bio, &cl, ca);
+		closure_sync(&cl);
 
 		/* This function could be simpler now since we no longer write
 		 * journal entries that overlap bucket boundaries; this means
@@ -72,7 +74,7 @@ reread:		left = ca->sb.bucket_size - offset;
 			struct list_head *where;
 			size_t blocks, bytes = set_bytes(j);
 
-			if (j->magic != jset_magic(ca->set))
+			if (j->magic != jset_magic(&ca->sb))
 				return ret;
 
 			if (bytes > left << 9)
@@ -129,12 +131,11 @@ next_set:
 	return ret;
 }
 
-int bch_journal_read(struct cache_set *c, struct list_head *list,
-			struct btree_op *op)
+int bch_journal_read(struct cache_set *c, struct list_head *list)
 {
 #define read_bucket(b)							\
 	({								\
-		int ret = journal_read_bucket(ca, list, op, b);		\
+		int ret = journal_read_bucket(ca, list, b);		\
 		__set_bit(b, bitmap);					\
 		if (ret < 0)						\
 			return ret;					\
@@ -292,8 +293,7 @@ void bch_journal_mark(struct cache_set *c, struct list_head *list)
 	}
 }
 
-int bch_journal_replay(struct cache_set *s, struct list_head *list,
-			  struct btree_op *op)
+int bch_journal_replay(struct cache_set *s, struct list_head *list)
 {
 	int ret = 0, keys = 0, entries = 0;
 	struct bkey *k;
@@ -301,31 +301,30 @@ int bch_journal_replay(struct cache_set *s, struct list_head *list,
 		list_entry(list->prev, struct journal_replay, list);
 
 	uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
+	struct keylist keylist;
+
+	bch_keylist_init(&keylist);
 
 	list_for_each_entry(i, list, list) {
 		BUG_ON(i->pin && atomic_read(i->pin) != 1);
 
-		if (n != i->j.seq)
-			pr_err(
-		"journal entries %llu-%llu missing! (replaying %llu-%llu)\n",
-		n, i->j.seq - 1, start, end);
+		cache_set_err_on(n != i->j.seq, s,
+"bcache: journal entries %llu-%llu missing! (replaying %llu-%llu)",
+				 n, i->j.seq - 1, start, end);
 
 		for (k = i->j.start;
 		     k < end(&i->j);
 		     k = bkey_next(k)) {
 			trace_bcache_journal_replay_key(k);
 
-			bkey_copy(op->keys.top, k);
-			bch_keylist_push(&op->keys);
-
-			op->journal = i->pin;
-			atomic_inc(op->journal);
+			bkey_copy(keylist.top, k);
+			bch_keylist_push(&keylist);
 
-			ret = bch_btree_insert(op, s);
+			ret = bch_btree_insert(s, &keylist, i->pin, NULL);
 			if (ret)
 				goto err;
 
-			BUG_ON(!bch_keylist_empty(&op->keys));
+			BUG_ON(!bch_keylist_empty(&keylist));
 			keys++;
 
 			cond_resched();
@@ -339,14 +338,13 @@ int bch_journal_replay(struct cache_set *s, struct list_head *list,
 
 	pr_info("journal replay done, %i keys in %i entries, seq %llu",
 		keys, entries, end);
-
+err:
 	while (!list_empty(list)) {
 		i = list_first_entry(list, struct journal_replay, list);
 		list_del(&i->list);
 		kfree(i);
 	}
-err:
-	closure_sync(&op->cl);
+
 	return ret;
 }
 
@@ -358,48 +356,35 @@ static void btree_flush_write(struct cache_set *c)
 	 * Try to find the btree node with that references the oldest journal
 	 * entry, best is our current candidate and is locked if non NULL:
 	 */
-	struct btree *b, *best = NULL;
-	unsigned iter;
+	struct btree *b, *best;
+	unsigned i;
+retry:
+	best = NULL;
+
+	for_each_cached_btree(b, c, i)
+		if (btree_current_write(b)->journal) {
+			if (!best)
+				best = b;
+			else if (journal_pin_cmp(c,
+					btree_current_write(best)->journal,
+					btree_current_write(b)->journal)) {
+				best = b;
+			}
+		}
 
-	for_each_cached_btree(b, c, iter) {
-		if (!down_write_trylock(&b->lock))
-			continue;
+	b = best;
+	if (b) {
+		rw_lock(true, b, b->level);
 
-		if (!btree_node_dirty(b) ||
-		    !btree_current_write(b)->journal) {
+		if (!btree_current_write(b)->journal) {
 			rw_unlock(true, b);
-			continue;
+			/* We raced */
+			goto retry;
 		}
 
-		if (!best)
-			best = b;
-		else if (journal_pin_cmp(c,
-					 btree_current_write(best),
-					 btree_current_write(b))) {
-			rw_unlock(true, best);
-			best = b;
-		} else
-			rw_unlock(true, b);
+		bch_btree_node_write(b, NULL);
+		rw_unlock(true, b);
 	}
-
-	if (best)
-		goto out;
-
-	/* We can't find the best btree node, just pick the first */
-	list_for_each_entry(b, &c->btree_cache, list)
-		if (!b->level && btree_node_dirty(b)) {
-			best = b;
-			rw_lock(true, best, best->level);
-			goto found;
-		}
-
-out:
-	if (!best)
-		return;
-found:
-	if (btree_node_dirty(best))
-		bch_btree_node_write(best, NULL);
-	rw_unlock(true, best);
 }
 
 #define last_seq(j)	((j)->seq - fifo_used(&(j)->pin) + 1)
@@ -495,7 +480,7 @@ static void journal_reclaim(struct cache_set *c)
 		do_journal_discard(ca);
 
 	if (c->journal.blocks_free)
-		return;
+		goto out;
 
 	/*
 	 * Allocate:
@@ -521,7 +506,7 @@ static void journal_reclaim(struct cache_set *c)
 
 	if (n)
 		c->journal.blocks_free = c->sb.bucket_size >> c->block_bits;
-
+out:
 	if (!journal_full(&c->journal))
 		__closure_wake_up(&c->journal.wait);
 }
@@ -554,32 +539,26 @@ static void journal_write_endio(struct bio *bio, int error)
 	struct journal_write *w = bio->bi_private;
 
 	cache_set_err_on(error, w->c, "journal io error");
-	closure_put(&w->c->journal.io.cl);
+	closure_put(&w->c->journal.io);
 }
 
 static void journal_write(struct closure *);
 
 static void journal_write_done(struct closure *cl)
 {
-	struct journal *j = container_of(cl, struct journal, io.cl);
-	struct cache_set *c = container_of(j, struct cache_set, journal);
-
+	struct journal *j = container_of(cl, struct journal, io);
 	struct journal_write *w = (j->cur == j->w)
 		? &j->w[1]
 		: &j->w[0];
 
 	__closure_wake_up(&w->wait);
-
-	if (c->journal_delay_ms)
-		closure_delay(&j->io, msecs_to_jiffies(c->journal_delay_ms));
-
-	continue_at(cl, journal_write, system_wq);
+	continue_at_nobarrier(cl, journal_write, system_wq);
 }
 
 static void journal_write_unlocked(struct closure *cl)
 	__releases(c->journal.lock)
 {
-	struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
+	struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 	struct cache *ca;
 	struct journal_write *w = c->journal.cur;
 	struct bkey *k = &c->journal.key;
@@ -617,7 +596,7 @@ static void journal_write_unlocked(struct closure *cl)
 	for_each_cache(ca, c, i)
 		w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
 
-	w->data->magic		= jset_magic(c);
+	w->data->magic		= jset_magic(&c->sb);
 	w->data->version	= BCACHE_JSET_VERSION;
 	w->data->last_seq	= last_seq(&c->journal);
 	w->data->csum		= csum_set(w->data);
@@ -660,121 +639,134 @@ static void journal_write_unlocked(struct closure *cl)
 
 static void journal_write(struct closure *cl)
 {
-	struct cache_set *c = container_of(cl, struct cache_set, journal.io.cl);
+	struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 
 	spin_lock(&c->journal.lock);
 	journal_write_unlocked(cl);
 }
 
-static void __journal_try_write(struct cache_set *c, bool noflush)
+static void journal_try_write(struct cache_set *c)
 	__releases(c->journal.lock)
 {
-	struct closure *cl = &c->journal.io.cl;
+	struct closure *cl = &c->journal.io;
+	struct journal_write *w = c->journal.cur;
 
-	if (!closure_trylock(cl, &c->cl))
-		spin_unlock(&c->journal.lock);
-	else if (noflush && journal_full(&c->journal)) {
-		spin_unlock(&c->journal.lock);
-		continue_at(cl, journal_write, system_wq);
-	} else
+	w->need_write = true;
+
+	if (closure_trylock(cl, &c->cl))
 		journal_write_unlocked(cl);
+	else
+		spin_unlock(&c->journal.lock);
 }
 
-#define journal_try_write(c)	__journal_try_write(c, false)
-
-void bch_journal_meta(struct cache_set *c, struct closure *cl)
+static struct journal_write *journal_wait_for_write(struct cache_set *c,
+						    unsigned nkeys)
 {
-	struct journal_write *w;
+	size_t sectors;
+	struct closure cl;
 
-	if (CACHE_SYNC(&c->sb)) {
-		spin_lock(&c->journal.lock);
+	closure_init_stack(&cl);
+
+	spin_lock(&c->journal.lock);
 
-		w = c->journal.cur;
-		w->need_write = true;
+	while (1) {
+		struct journal_write *w = c->journal.cur;
 
-		if (cl)
-			BUG_ON(!closure_wait(&w->wait, cl));
+		sectors = __set_blocks(w->data, w->data->keys + nkeys,
+				       c) * c->sb.block_size;
 
-		closure_flush(&c->journal.io);
-		__journal_try_write(c, true);
+		if (sectors <= min_t(size_t,
+				     c->journal.blocks_free * c->sb.block_size,
+				     PAGE_SECTORS << JSET_BITS))
+			return w;
+
+		/* XXX: tracepoint */
+		if (!journal_full(&c->journal)) {
+			trace_bcache_journal_entry_full(c);
+
+			/*
+			 * XXX: If we were inserting so many keys that they
+			 * won't fit in an _empty_ journal write, we'll
+			 * deadlock. For now, handle this in
+			 * bch_keylist_realloc() - but something to think about.
+			 */
+			BUG_ON(!w->data->keys);
+
+			closure_wait(&w->wait, &cl);
+			journal_try_write(c); /* unlocks */
+		} else {
+			trace_bcache_journal_full(c);
+
+			closure_wait(&c->journal.wait, &cl);
+			journal_reclaim(c);
+			spin_unlock(&c->journal.lock);
+
+			btree_flush_write(c);
+		}
+
+		closure_sync(&cl);
+		spin_lock(&c->journal.lock);
 	}
 }
 
+static void journal_write_work(struct work_struct *work)
+{
+	struct cache_set *c = container_of(to_delayed_work(work),
+					   struct cache_set,
+					   journal.work);
+	spin_lock(&c->journal.lock);
+	journal_try_write(c);
+}
+
 /*
  * Entry point to the journalling code - bio_insert() and btree_invalidate()
  * pass bch_journal() a list of keys to be journalled, and then
  * bch_journal() hands those same keys off to btree_insert_async()
  */
 
-void bch_journal(struct closure *cl)
+atomic_t *bch_journal(struct cache_set *c,
+		      struct keylist *keys,
+		      struct closure *parent)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-	struct cache_set *c = op->c;
 	struct journal_write *w;
-	size_t b, n = ((uint64_t *) op->keys.top) - op->keys.list;
-
-	if (op->type != BTREE_INSERT ||
-	    !CACHE_SYNC(&c->sb))
-		goto out;
+	atomic_t *ret;
 
-	/*
-	 * If we're looping because we errored, might already be waiting on
-	 * another journal write:
-	 */
-	while (atomic_read(&cl->parent->remaining) & CLOSURE_WAITING)
-		closure_sync(cl->parent);
+	if (!CACHE_SYNC(&c->sb))
+		return NULL;
 
-	spin_lock(&c->journal.lock);
+	w = journal_wait_for_write(c, bch_keylist_nkeys(keys));
 
-	if (journal_full(&c->journal)) {
-		trace_bcache_journal_full(c);
+	memcpy(end(w->data), keys->keys, bch_keylist_bytes(keys));
+	w->data->keys += bch_keylist_nkeys(keys);
 
-		closure_wait(&c->journal.wait, cl);
+	ret = &fifo_back(&c->journal.pin);
+	atomic_inc(ret);
 
-		journal_reclaim(c);
+	if (parent) {
+		closure_wait(&w->wait, parent);
+		journal_try_write(c);
+	} else if (!w->need_write) {
+		schedule_delayed_work(&c->journal.work,
+				      msecs_to_jiffies(c->journal_delay_ms));
+		spin_unlock(&c->journal.lock);
+	} else {
 		spin_unlock(&c->journal.lock);
-
-		btree_flush_write(c);
-		continue_at(cl, bch_journal, bcache_wq);
 	}
 
-	w = c->journal.cur;
-	w->need_write = true;
-	b = __set_blocks(w->data, w->data->keys + n, c);
-
-	if (b * c->sb.block_size > PAGE_SECTORS << JSET_BITS ||
-	    b > c->journal.blocks_free) {
-		trace_bcache_journal_entry_full(c);
-
-		/*
-		 * XXX: If we were inserting so many keys that they won't fit in
-		 * an _empty_ journal write, we'll deadlock. For now, handle
-		 * this in bch_keylist_realloc() - but something to think about.
-		 */
-		BUG_ON(!w->data->keys);
-
-		BUG_ON(!closure_wait(&w->wait, cl));
-
-		closure_flush(&c->journal.io);
 
-		journal_try_write(c);
-		continue_at(cl, bch_journal, bcache_wq);
-	}
-
-	memcpy(end(w->data), op->keys.list, n * sizeof(uint64_t));
-	w->data->keys += n;
+	return ret;
+}
 
-	op->journal = &fifo_back(&c->journal.pin);
-	atomic_inc(op->journal);
+void bch_journal_meta(struct cache_set *c, struct closure *cl)
+{
+	struct keylist keys;
+	atomic_t *ref;
 
-	if (op->flush_journal) {
-		closure_flush(&c->journal.io);
-		closure_wait(&w->wait, cl->parent);
-	}
+	bch_keylist_init(&keys);
 
-	journal_try_write(c);
-out:
-	bch_btree_insert_async(cl);
+	ref = bch_journal(c, &keys, cl);
+	if (ref)
+		atomic_dec_bug(ref);
 }
 
 void bch_journal_free(struct cache_set *c)
@@ -790,6 +782,7 @@ int bch_journal_alloc(struct cache_set *c)
 
 	closure_init_unlocked(&j->io);
 	spin_lock_init(&j->lock);
+	INIT_DELAYED_WORK(&j->work, journal_write_work);
 
 	c->journal_delay_ms = 100;
 
diff --git a/drivers/md/bcache/journal.h b/drivers/md/bcache/journal.h
index 3d7851274b04..a6472fda94b2 100644
--- a/drivers/md/bcache/journal.h
+++ b/drivers/md/bcache/journal.h
@@ -75,43 +75,6 @@
  * nodes that are pinning the oldest journal entries first.
  */
 
-#define BCACHE_JSET_VERSION_UUIDv1	1
-/* Always latest UUID format */
-#define BCACHE_JSET_VERSION_UUID	1
-#define BCACHE_JSET_VERSION		1
-
-/*
- * On disk format for a journal entry:
- * seq is monotonically increasing; every journal entry has its own unique
- * sequence number.
- *
- * last_seq is the oldest journal entry that still has keys the btree hasn't
- * flushed to disk yet.
- *
- * version is for on disk format changes.
- */
-struct jset {
-	uint64_t		csum;
-	uint64_t		magic;
-	uint64_t		seq;
-	uint32_t		version;
-	uint32_t		keys;
-
-	uint64_t		last_seq;
-
-	BKEY_PADDED(uuid_bucket);
-	BKEY_PADDED(btree_root);
-	uint16_t		btree_level;
-	uint16_t		pad[3];
-
-	uint64_t		prio_bucket[MAX_CACHES_PER_SET];
-
-	union {
-		struct bkey	start[0];
-		uint64_t	d[0];
-	};
-};
-
 /*
  * Only used for holding the journal entries we read in btree_journal_read()
  * during cache_registration
@@ -140,7 +103,8 @@ struct journal {
 	spinlock_t		lock;
 	/* used when waiting because the journal was full */
 	struct closure_waitlist	wait;
-	struct closure_with_timer io;
+	struct closure		io;
+	struct delayed_work	work;
 
 	/* Number of blocks free in the bucket(s) we're currently writing to */
 	unsigned		blocks_free;
@@ -188,8 +152,7 @@ struct journal_device {
 };
 
 #define journal_pin_cmp(c, l, r)				\
-	(fifo_idx(&(c)->journal.pin, (l)->journal) >		\
-	 fifo_idx(&(c)->journal.pin, (r)->journal))
+	(fifo_idx(&(c)->journal.pin, (l)) > fifo_idx(&(c)->journal.pin, (r)))
 
 #define JOURNAL_PIN	20000
 
@@ -199,15 +162,14 @@ struct journal_device {
 struct closure;
 struct cache_set;
 struct btree_op;
+struct keylist;
 
-void bch_journal(struct closure *);
+atomic_t *bch_journal(struct cache_set *, struct keylist *, struct closure *);
 void bch_journal_next(struct journal *);
 void bch_journal_mark(struct cache_set *, struct list_head *);
 void bch_journal_meta(struct cache_set *, struct closure *);
-int bch_journal_read(struct cache_set *, struct list_head *,
-			struct btree_op *);
-int bch_journal_replay(struct cache_set *, struct list_head *,
-			  struct btree_op *);
+int bch_journal_read(struct cache_set *, struct list_head *);
+int bch_journal_replay(struct cache_set *, struct list_head *);
 
 void bch_journal_free(struct cache_set *);
 int bch_journal_alloc(struct cache_set *);
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c
index 1a3b4f4786c3..7c1275e66025 100644
--- a/drivers/md/bcache/movinggc.c
+++ b/drivers/md/bcache/movinggc.c
@@ -12,8 +12,9 @@
 #include <trace/events/bcache.h>
 
 struct moving_io {
+	struct closure		cl;
 	struct keybuf_key	*w;
-	struct search		s;
+	struct data_insert_op	op;
 	struct bbio		bio;
 };
 
@@ -38,13 +39,13 @@ static bool moving_pred(struct keybuf *buf, struct bkey *k)
 
 static void moving_io_destructor(struct closure *cl)
 {
-	struct moving_io *io = container_of(cl, struct moving_io, s.cl);
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
 	kfree(io);
 }
 
 static void write_moving_finish(struct closure *cl)
 {
-	struct moving_io *io = container_of(cl, struct moving_io, s.cl);
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
 	struct bio *bio = &io->bio.bio;
 	struct bio_vec *bv;
 	int i;
@@ -52,13 +53,12 @@ static void write_moving_finish(struct closure *cl)
 	bio_for_each_segment_all(bv, bio, i)
 		__free_page(bv->bv_page);
 
-	if (io->s.op.insert_collision)
+	if (io->op.replace_collision)
 		trace_bcache_gc_copy_collision(&io->w->key);
 
-	bch_keybuf_del(&io->s.op.c->moving_gc_keys, io->w);
+	bch_keybuf_del(&io->op.c->moving_gc_keys, io->w);
 
-	atomic_dec_bug(&io->s.op.c->in_flight);
-	closure_wake_up(&io->s.op.c->moving_gc_wait);
+	up(&io->op.c->moving_in_flight);
 
 	closure_return_with_destructor(cl, moving_io_destructor);
 }
@@ -66,12 +66,12 @@ static void write_moving_finish(struct closure *cl)
 static void read_moving_endio(struct bio *bio, int error)
 {
 	struct moving_io *io = container_of(bio->bi_private,
-					    struct moving_io, s.cl);
+					    struct moving_io, cl);
 
 	if (error)
-		io->s.error = error;
+		io->op.error = error;
 
-	bch_bbio_endio(io->s.op.c, bio, error, "reading data to move");
+	bch_bbio_endio(io->op.c, bio, error, "reading data to move");
 }
 
 static void moving_init(struct moving_io *io)
@@ -85,54 +85,53 @@ static void moving_init(struct moving_io *io)
 	bio->bi_size		= KEY_SIZE(&io->w->key) << 9;
 	bio->bi_max_vecs	= DIV_ROUND_UP(KEY_SIZE(&io->w->key),
 					       PAGE_SECTORS);
-	bio->bi_private		= &io->s.cl;
+	bio->bi_private		= &io->cl;
 	bio->bi_io_vec		= bio->bi_inline_vecs;
 	bch_bio_map(bio, NULL);
 }
 
 static void write_moving(struct closure *cl)
 {
-	struct search *s = container_of(cl, struct search, cl);
-	struct moving_io *io = container_of(s, struct moving_io, s);
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
+	struct data_insert_op *op = &io->op;
 
-	if (!s->error) {
+	if (!op->error) {
 		moving_init(io);
 
-		io->bio.bio.bi_sector	= KEY_START(&io->w->key);
-		s->op.lock		= -1;
-		s->op.write_prio	= 1;
-		s->op.cache_bio		= &io->bio.bio;
+		io->bio.bio.bi_sector = KEY_START(&io->w->key);
+		op->write_prio		= 1;
+		op->bio			= &io->bio.bio;
 
-		s->writeback		= KEY_DIRTY(&io->w->key);
-		s->op.csum		= KEY_CSUM(&io->w->key);
+		op->writeback		= KEY_DIRTY(&io->w->key);
+		op->csum		= KEY_CSUM(&io->w->key);
 
-		s->op.type = BTREE_REPLACE;
-		bkey_copy(&s->op.replace, &io->w->key);
+		bkey_copy(&op->replace_key, &io->w->key);
+		op->replace		= true;
 
-		closure_init(&s->op.cl, cl);
-		bch_insert_data(&s->op.cl);
+		closure_call(&op->cl, bch_data_insert, NULL, cl);
 	}
 
-	continue_at(cl, write_moving_finish, NULL);
+	continue_at(cl, write_moving_finish, system_wq);
 }
 
 static void read_moving_submit(struct closure *cl)
 {
-	struct search *s = container_of(cl, struct search, cl);
-	struct moving_io *io = container_of(s, struct moving_io, s);
+	struct moving_io *io = container_of(cl, struct moving_io, cl);
 	struct bio *bio = &io->bio.bio;
 
-	bch_submit_bbio(bio, s->op.c, &io->w->key, 0);
+	bch_submit_bbio(bio, io->op.c, &io->w->key, 0);
 
-	continue_at(cl, write_moving, bch_gc_wq);
+	continue_at(cl, write_moving, system_wq);
 }
 
-static void read_moving(struct closure *cl)
+static void read_moving(struct cache_set *c)
 {
-	struct cache_set *c = container_of(cl, struct cache_set, moving_gc);
 	struct keybuf_key *w;
 	struct moving_io *io;
 	struct bio *bio;
+	struct closure cl;
+
+	closure_init_stack(&cl);
 
 	/* XXX: if we error, background writeback could stall indefinitely */
 
@@ -150,8 +149,8 @@ static void read_moving(struct closure *cl)
 
 		w->private	= io;
 		io->w		= w;
-		io->s.op.inode	= KEY_INODE(&w->key);
-		io->s.op.c	= c;
+		io->op.inode	= KEY_INODE(&w->key);
+		io->op.c	= c;
 
 		moving_init(io);
 		bio = &io->bio.bio;
@@ -164,13 +163,8 @@ static void read_moving(struct closure *cl)
 
 		trace_bcache_gc_copy(&w->key);
 
-		closure_call(&io->s.cl, read_moving_submit, NULL, &c->gc.cl);
-
-		if (atomic_inc_return(&c->in_flight) >= 64) {
-			closure_wait_event(&c->moving_gc_wait, cl,
-					   atomic_read(&c->in_flight) < 64);
-			continue_at(cl, read_moving, bch_gc_wq);
-		}
+		down(&c->moving_in_flight);
+		closure_call(&io->cl, read_moving_submit, NULL, &cl);
 	}
 
 	if (0) {
@@ -180,7 +174,7 @@ err:		if (!IS_ERR_OR_NULL(w->private))
 		bch_keybuf_del(&c->moving_gc_keys, w);
 	}
 
-	closure_return(cl);
+	closure_sync(&cl);
 }
 
 static bool bucket_cmp(struct bucket *l, struct bucket *r)
@@ -193,15 +187,14 @@ static unsigned bucket_heap_top(struct cache *ca)
 	return GC_SECTORS_USED(heap_peek(&ca->heap));
 }
 
-void bch_moving_gc(struct closure *cl)
+void bch_moving_gc(struct cache_set *c)
 {
-	struct cache_set *c = container_of(cl, struct cache_set, gc.cl);
 	struct cache *ca;
 	struct bucket *b;
 	unsigned i;
 
 	if (!c->copy_gc_enabled)
-		closure_return(cl);
+		return;
 
 	mutex_lock(&c->bucket_lock);
 
@@ -242,13 +235,11 @@ void bch_moving_gc(struct closure *cl)
 
 	c->moving_gc_keys.last_scanned = ZERO_KEY;
 
-	closure_init(&c->moving_gc, cl);
-	read_moving(&c->moving_gc);
-
-	closure_return(cl);
+	read_moving(c);
 }
 
 void bch_moving_init_cache_set(struct cache_set *c)
 {
 	bch_keybuf_init(&c->moving_gc_keys);
+	sema_init(&c->moving_in_flight, 64);
 }
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 2a7f0dd6abab..fbcc851ed5a5 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -25,7 +25,7 @@
 
 struct kmem_cache *bch_search_cache;
 
-static void check_should_skip(struct cached_dev *, struct search *);
+static void bch_data_insert_start(struct closure *);
 
 /* Cgroup interface */
 
@@ -213,221 +213,79 @@ static void bio_csum(struct bio *bio, struct bkey *k)
 
 /* Insert data into cache */
 
-static void bio_invalidate(struct closure *cl)
+static void bch_data_insert_keys(struct closure *cl)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-	struct bio *bio = op->cache_bio;
-
-	pr_debug("invalidating %i sectors from %llu",
-		 bio_sectors(bio), (uint64_t) bio->bi_sector);
-
-	while (bio_sectors(bio)) {
-		unsigned len = min(bio_sectors(bio), 1U << 14);
-
-		if (bch_keylist_realloc(&op->keys, 0, op->c))
-			goto out;
-
-		bio->bi_sector	+= len;
-		bio->bi_size	-= len << 9;
-
-		bch_keylist_add(&op->keys,
-				&KEY(op->inode, bio->bi_sector, len));
-	}
-
-	op->insert_data_done = true;
-	bio_put(bio);
-out:
-	continue_at(cl, bch_journal, bcache_wq);
-}
-
-struct open_bucket {
-	struct list_head	list;
-	struct task_struct	*last;
-	unsigned		sectors_free;
-	BKEY_PADDED(key);
-};
-
-void bch_open_buckets_free(struct cache_set *c)
-{
-	struct open_bucket *b;
-
-	while (!list_empty(&c->data_buckets)) {
-		b = list_first_entry(&c->data_buckets,
-				     struct open_bucket, list);
-		list_del(&b->list);
-		kfree(b);
-	}
-}
-
-int bch_open_buckets_alloc(struct cache_set *c)
-{
-	int i;
-
-	spin_lock_init(&c->data_bucket_lock);
-
-	for (i = 0; i < 6; i++) {
-		struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
-		if (!b)
-			return -ENOMEM;
-
-		list_add(&b->list, &c->data_buckets);
-	}
-
-	return 0;
-}
-
-/*
- * We keep multiple buckets open for writes, and try to segregate different
- * write streams for better cache utilization: first we look for a bucket where
- * the last write to it was sequential with the current write, and failing that
- * we look for a bucket that was last used by the same task.
- *
- * The ideas is if you've got multiple tasks pulling data into the cache at the
- * same time, you'll get better cache utilization if you try to segregate their
- * data and preserve locality.
- *
- * For example, say you've starting Firefox at the same time you're copying a
- * bunch of files. Firefox will likely end up being fairly hot and stay in the
- * cache awhile, but the data you copied might not be; if you wrote all that
- * data to the same buckets it'd get invalidated at the same time.
- *
- * Both of those tasks will be doing fairly random IO so we can't rely on
- * detecting sequential IO to segregate their data, but going off of the task
- * should be a sane heuristic.
- */
-static struct open_bucket *pick_data_bucket(struct cache_set *c,
-					    const struct bkey *search,
-					    struct task_struct *task,
-					    struct bkey *alloc)
-{
-	struct open_bucket *ret, *ret_task = NULL;
-
-	list_for_each_entry_reverse(ret, &c->data_buckets, list)
-		if (!bkey_cmp(&ret->key, search))
-			goto found;
-		else if (ret->last == task)
-			ret_task = ret;
-
-	ret = ret_task ?: list_first_entry(&c->data_buckets,
-					   struct open_bucket, list);
-found:
-	if (!ret->sectors_free && KEY_PTRS(alloc)) {
-		ret->sectors_free = c->sb.bucket_size;
-		bkey_copy(&ret->key, alloc);
-		bkey_init(alloc);
-	}
-
-	if (!ret->sectors_free)
-		ret = NULL;
-
-	return ret;
-}
-
-/*
- * Allocates some space in the cache to write to, and k to point to the newly
- * allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
- * end of the newly allocated space).
- *
- * May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
- * sectors were actually allocated.
- *
- * If s->writeback is true, will not fail.
- */
-static bool bch_alloc_sectors(struct bkey *k, unsigned sectors,
-			      struct search *s)
-{
-	struct cache_set *c = s->op.c;
-	struct open_bucket *b;
-	BKEY_PADDED(key) alloc;
-	struct closure cl, *w = NULL;
-	unsigned i;
-
-	if (s->writeback) {
-		closure_init_stack(&cl);
-		w = &cl;
-	}
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
+	atomic_t *journal_ref = NULL;
+	struct bkey *replace_key = op->replace ? &op->replace_key : NULL;
+	int ret;
 
 	/*
-	 * We might have to allocate a new bucket, which we can't do with a
-	 * spinlock held. So if we have to allocate, we drop the lock, allocate
-	 * and then retry. KEY_PTRS() indicates whether alloc points to
-	 * allocated bucket(s).
+	 * If we're looping, might already be waiting on
+	 * another journal write - can't wait on more than one journal write at
+	 * a time
+	 *
+	 * XXX: this looks wrong
 	 */
+#if 0
+	while (atomic_read(&s->cl.remaining) & CLOSURE_WAITING)
+		closure_sync(&s->cl);
+#endif
 
-	bkey_init(&alloc.key);
-	spin_lock(&c->data_bucket_lock);
-
-	while (!(b = pick_data_bucket(c, k, s->task, &alloc.key))) {
-		unsigned watermark = s->op.write_prio
-			? WATERMARK_MOVINGGC
-			: WATERMARK_NONE;
-
-		spin_unlock(&c->data_bucket_lock);
-
-		if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, w))
-			return false;
+	if (!op->replace)
+		journal_ref = bch_journal(op->c, &op->insert_keys,
+					  op->flush_journal ? cl : NULL);
 
-		spin_lock(&c->data_bucket_lock);
+	ret = bch_btree_insert(op->c, &op->insert_keys,
+			       journal_ref, replace_key);
+	if (ret == -ESRCH) {
+		op->replace_collision = true;
+	} else if (ret) {
+		op->error		= -ENOMEM;
+		op->insert_data_done	= true;
 	}
 
-	/*
-	 * If we had to allocate, we might race and not need to allocate the
-	 * second time we call find_data_bucket(). If we allocated a bucket but
-	 * didn't use it, drop the refcount bch_bucket_alloc_set() took:
-	 */
-	if (KEY_PTRS(&alloc.key))
-		__bkey_put(c, &alloc.key);
-
-	for (i = 0; i < KEY_PTRS(&b->key); i++)
-		EBUG_ON(ptr_stale(c, &b->key, i));
+	if (journal_ref)
+		atomic_dec_bug(journal_ref);
 
-	/* Set up the pointer to the space we're allocating: */
+	if (!op->insert_data_done)
+		continue_at(cl, bch_data_insert_start, bcache_wq);
 
-	for (i = 0; i < KEY_PTRS(&b->key); i++)
-		k->ptr[i] = b->key.ptr[i];
+	bch_keylist_free(&op->insert_keys);
+	closure_return(cl);
+}
 
-	sectors = min(sectors, b->sectors_free);
+static void bch_data_invalidate(struct closure *cl)
+{
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
+	struct bio *bio = op->bio;
 
-	SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
-	SET_KEY_SIZE(k, sectors);
-	SET_KEY_PTRS(k, KEY_PTRS(&b->key));
+	pr_debug("invalidating %i sectors from %llu",
+		 bio_sectors(bio), (uint64_t) bio->bi_sector);
 
-	/*
-	 * Move b to the end of the lru, and keep track of what this bucket was
-	 * last used for:
-	 */
-	list_move_tail(&b->list, &c->data_buckets);
-	bkey_copy_key(&b->key, k);
-	b->last = s->task;
+	while (bio_sectors(bio)) {
+		unsigned sectors = min(bio_sectors(bio),
+				       1U << (KEY_SIZE_BITS - 1));
 
-	b->sectors_free	-= sectors;
+		if (bch_keylist_realloc(&op->insert_keys, 0, op->c))
+			goto out;
 
-	for (i = 0; i < KEY_PTRS(&b->key); i++) {
-		SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
+		bio->bi_sector	+= sectors;
+		bio->bi_size	-= sectors << 9;
 
-		atomic_long_add(sectors,
-				&PTR_CACHE(c, &b->key, i)->sectors_written);
+		bch_keylist_add(&op->insert_keys,
+				&KEY(op->inode, bio->bi_sector, sectors));
 	}
 
-	if (b->sectors_free < c->sb.block_size)
-		b->sectors_free = 0;
-
-	/*
-	 * k takes refcounts on the buckets it points to until it's inserted
-	 * into the btree, but if we're done with this bucket we just transfer
-	 * get_data_bucket()'s refcount.
-	 */
-	if (b->sectors_free)
-		for (i = 0; i < KEY_PTRS(&b->key); i++)
-			atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
-
-	spin_unlock(&c->data_bucket_lock);
-	return true;
+	op->insert_data_done = true;
+	bio_put(bio);
+out:
+	continue_at(cl, bch_data_insert_keys, bcache_wq);
 }
 
-static void bch_insert_data_error(struct closure *cl)
+static void bch_data_insert_error(struct closure *cl)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
 
 	/*
 	 * Our data write just errored, which means we've got a bunch of keys to
@@ -438,35 +296,34 @@ static void bch_insert_data_error(struct closure *cl)
 	 * from the keys we'll accomplish just that.
 	 */
 
-	struct bkey *src = op->keys.bottom, *dst = op->keys.bottom;
+	struct bkey *src = op->insert_keys.keys, *dst = op->insert_keys.keys;
 
-	while (src != op->keys.top) {
+	while (src != op->insert_keys.top) {
 		struct bkey *n = bkey_next(src);
 
 		SET_KEY_PTRS(src, 0);
-		bkey_copy(dst, src);
+		memmove(dst, src, bkey_bytes(src));
 
 		dst = bkey_next(dst);
 		src = n;
 	}
 
-	op->keys.top = dst;
+	op->insert_keys.top = dst;
 
-	bch_journal(cl);
+	bch_data_insert_keys(cl);
 }
 
-static void bch_insert_data_endio(struct bio *bio, int error)
+static void bch_data_insert_endio(struct bio *bio, int error)
 {
 	struct closure *cl = bio->bi_private;
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-	struct search *s = container_of(op, struct search, op);
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
 
 	if (error) {
 		/* TODO: We could try to recover from this. */
-		if (s->writeback)
-			s->error = error;
-		else if (s->write)
-			set_closure_fn(cl, bch_insert_data_error, bcache_wq);
+		if (op->writeback)
+			op->error = error;
+		else if (!op->replace)
+			set_closure_fn(cl, bch_data_insert_error, bcache_wq);
 		else
 			set_closure_fn(cl, NULL, NULL);
 	}
@@ -474,18 +331,17 @@ static void bch_insert_data_endio(struct bio *bio, int error)
 	bch_bbio_endio(op->c, bio, error, "writing data to cache");
 }
 
-static void bch_insert_data_loop(struct closure *cl)
+static void bch_data_insert_start(struct closure *cl)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-	struct search *s = container_of(op, struct search, op);
-	struct bio *bio = op->cache_bio, *n;
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
+	struct bio *bio = op->bio, *n;
 
-	if (op->skip)
-		return bio_invalidate(cl);
+	if (op->bypass)
+		return bch_data_invalidate(cl);
 
 	if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) {
 		set_gc_sectors(op->c);
-		bch_queue_gc(op->c);
+		wake_up_gc(op->c);
 	}
 
 	/*
@@ -497,29 +353,30 @@ static void bch_insert_data_loop(struct closure *cl)
 	do {
 		unsigned i;
 		struct bkey *k;
-		struct bio_set *split = s->d
-			? s->d->bio_split : op->c->bio_split;
+		struct bio_set *split = op->c->bio_split;
 
 		/* 1 for the device pointer and 1 for the chksum */
-		if (bch_keylist_realloc(&op->keys,
+		if (bch_keylist_realloc(&op->insert_keys,
 					1 + (op->csum ? 1 : 0),
 					op->c))
-			continue_at(cl, bch_journal, bcache_wq);
+			continue_at(cl, bch_data_insert_keys, bcache_wq);
 
-		k = op->keys.top;
+		k = op->insert_keys.top;
 		bkey_init(k);
 		SET_KEY_INODE(k, op->inode);
 		SET_KEY_OFFSET(k, bio->bi_sector);
 
-		if (!bch_alloc_sectors(k, bio_sectors(bio), s))
+		if (!bch_alloc_sectors(op->c, k, bio_sectors(bio),
+				       op->write_point, op->write_prio,
+				       op->writeback))
 			goto err;
 
 		n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
 
-		n->bi_end_io	= bch_insert_data_endio;
+		n->bi_end_io	= bch_data_insert_endio;
 		n->bi_private	= cl;
 
-		if (s->writeback) {
+		if (op->writeback) {
 			SET_KEY_DIRTY(k, true);
 
 			for (i = 0; i < KEY_PTRS(k); i++)
@@ -532,17 +389,17 @@ static void bch_insert_data_loop(struct closure *cl)
 			bio_csum(n, k);
 
 		trace_bcache_cache_insert(k);
-		bch_keylist_push(&op->keys);
+		bch_keylist_push(&op->insert_keys);
 
 		n->bi_rw |= REQ_WRITE;
 		bch_submit_bbio(n, op->c, k, 0);
 	} while (n != bio);
 
 	op->insert_data_done = true;
-	continue_at(cl, bch_journal, bcache_wq);
+	continue_at(cl, bch_data_insert_keys, bcache_wq);
 err:
 	/* bch_alloc_sectors() blocks if s->writeback = true */
-	BUG_ON(s->writeback);
+	BUG_ON(op->writeback);
 
 	/*
 	 * But if it's not a writeback write we'd rather just bail out if
@@ -550,15 +407,15 @@ err:
 	 * we might be starving btree writes for gc or something.
 	 */
 
-	if (s->write) {
+	if (!op->replace) {
 		/*
 		 * Writethrough write: We can't complete the write until we've
 		 * updated the index. But we don't want to delay the write while
 		 * we wait for buckets to be freed up, so just invalidate the
 		 * rest of the write.
 		 */
-		op->skip = true;
-		return bio_invalidate(cl);
+		op->bypass = true;
+		return bch_data_invalidate(cl);
 	} else {
 		/*
 		 * From a cache miss, we can just insert the keys for the data
@@ -567,15 +424,15 @@ err:
 		op->insert_data_done = true;
 		bio_put(bio);
 
-		if (!bch_keylist_empty(&op->keys))
-			continue_at(cl, bch_journal, bcache_wq);
+		if (!bch_keylist_empty(&op->insert_keys))
+			continue_at(cl, bch_data_insert_keys, bcache_wq);
 		else
 			closure_return(cl);
 	}
 }
 
 /**
- * bch_insert_data - stick some data in the cache
+ * bch_data_insert - stick some data in the cache
  *
  * This is the starting point for any data to end up in a cache device; it could
  * be from a normal write, or a writeback write, or a write to a flash only
@@ -587,56 +444,179 @@ err:
  * data is written it calls bch_journal, and after the keys have been added to
  * the next journal write they're inserted into the btree.
  *
- * It inserts the data in op->cache_bio; bi_sector is used for the key offset,
+ * It inserts the data in s->cache_bio; bi_sector is used for the key offset,
  * and op->inode is used for the key inode.
  *
- * If op->skip is true, instead of inserting the data it invalidates the region
- * of the cache represented by op->cache_bio and op->inode.
+ * If s->bypass is true, instead of inserting the data it invalidates the
+ * region of the cache represented by s->cache_bio and op->inode.
  */
-void bch_insert_data(struct closure *cl)
+void bch_data_insert(struct closure *cl)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
+	struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
+
+	trace_bcache_write(op->bio, op->writeback, op->bypass);
 
-	bch_keylist_init(&op->keys);
-	bio_get(op->cache_bio);
-	bch_insert_data_loop(cl);
+	bch_keylist_init(&op->insert_keys);
+	bio_get(op->bio);
+	bch_data_insert_start(cl);
 }
 
-void bch_btree_insert_async(struct closure *cl)
+/* Congested? */
+
+unsigned bch_get_congested(struct cache_set *c)
 {
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-	struct search *s = container_of(op, struct search, op);
+	int i;
+	long rand;
 
-	if (bch_btree_insert(op, op->c)) {
-		s->error		= -ENOMEM;
-		op->insert_data_done	= true;
-	}
+	if (!c->congested_read_threshold_us &&
+	    !c->congested_write_threshold_us)
+		return 0;
+
+	i = (local_clock_us() - c->congested_last_us) / 1024;
+	if (i < 0)
+		return 0;
+
+	i += atomic_read(&c->congested);
+	if (i >= 0)
+		return 0;
 
-	if (op->insert_data_done) {
-		bch_keylist_free(&op->keys);
-		closure_return(cl);
-	} else
-		continue_at(cl, bch_insert_data_loop, bcache_wq);
+	i += CONGESTED_MAX;
+
+	if (i > 0)
+		i = fract_exp_two(i, 6);
+
+	rand = get_random_int();
+	i -= bitmap_weight(&rand, BITS_PER_LONG);
+
+	return i > 0 ? i : 1;
 }
 
-/* Common code for the make_request functions */
+static void add_sequential(struct task_struct *t)
+{
+	ewma_add(t->sequential_io_avg,
+		 t->sequential_io, 8, 0);
 
-static void request_endio(struct bio *bio, int error)
+	t->sequential_io = 0;
+}
+
+static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k)
 {
-	struct closure *cl = bio->bi_private;
+	return &dc->io_hash[hash_64(k, RECENT_IO_BITS)];
+}
 
-	if (error) {
-		struct search *s = container_of(cl, struct search, cl);
-		s->error = error;
-		/* Only cache read errors are recoverable */
-		s->recoverable = false;
+static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
+{
+	struct cache_set *c = dc->disk.c;
+	unsigned mode = cache_mode(dc, bio);
+	unsigned sectors, congested = bch_get_congested(c);
+	struct task_struct *task = current;
+	struct io *i;
+
+	if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
+	    c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
+	    (bio->bi_rw & REQ_DISCARD))
+		goto skip;
+
+	if (mode == CACHE_MODE_NONE ||
+	    (mode == CACHE_MODE_WRITEAROUND &&
+	     (bio->bi_rw & REQ_WRITE)))
+		goto skip;
+
+	if (bio->bi_sector & (c->sb.block_size - 1) ||
+	    bio_sectors(bio) & (c->sb.block_size - 1)) {
+		pr_debug("skipping unaligned io");
+		goto skip;
 	}
 
-	bio_put(bio);
-	closure_put(cl);
+	if (bypass_torture_test(dc)) {
+		if ((get_random_int() & 3) == 3)
+			goto skip;
+		else
+			goto rescale;
+	}
+
+	if (!congested && !dc->sequential_cutoff)
+		goto rescale;
+
+	if (!congested &&
+	    mode == CACHE_MODE_WRITEBACK &&
+	    (bio->bi_rw & REQ_WRITE) &&
+	    (bio->bi_rw & REQ_SYNC))
+		goto rescale;
+
+	spin_lock(&dc->io_lock);
+
+	hlist_for_each_entry(i, iohash(dc, bio->bi_sector), hash)
+		if (i->last == bio->bi_sector &&
+		    time_before(jiffies, i->jiffies))
+			goto found;
+
+	i = list_first_entry(&dc->io_lru, struct io, lru);
+
+	add_sequential(task);
+	i->sequential = 0;
+found:
+	if (i->sequential + bio->bi_size > i->sequential)
+		i->sequential	+= bio->bi_size;
+
+	i->last			 = bio_end_sector(bio);
+	i->jiffies		 = jiffies + msecs_to_jiffies(5000);
+	task->sequential_io	 = i->sequential;
+
+	hlist_del(&i->hash);
+	hlist_add_head(&i->hash, iohash(dc, i->last));
+	list_move_tail(&i->lru, &dc->io_lru);
+
+	spin_unlock(&dc->io_lock);
+
+	sectors = max(task->sequential_io,
+		      task->sequential_io_avg) >> 9;
+
+	if (dc->sequential_cutoff &&
+	    sectors >= dc->sequential_cutoff >> 9) {
+		trace_bcache_bypass_sequential(bio);
+		goto skip;
+	}
+
+	if (congested && sectors >= congested) {
+		trace_bcache_bypass_congested(bio);
+		goto skip;
+	}
+
+rescale:
+	bch_rescale_priorities(c, bio_sectors(bio));
+	return false;
+skip:
+	bch_mark_sectors_bypassed(c, dc, bio_sectors(bio));
+	return true;
 }
 
-void bch_cache_read_endio(struct bio *bio, int error)
+/* Cache lookup */
+
+struct search {
+	/* Stack frame for bio_complete */
+	struct closure		cl;
+
+	struct bcache_device	*d;
+
+	struct bbio		bio;
+	struct bio		*orig_bio;
+	struct bio		*cache_miss;
+
+	unsigned		insert_bio_sectors;
+
+	unsigned		recoverable:1;
+	unsigned		unaligned_bvec:1;
+	unsigned		write:1;
+	unsigned		read_dirty_data:1;
+
+	unsigned long		start_time;
+
+	struct btree_op		op;
+	struct data_insert_op	iop;
+};
+
+static void bch_cache_read_endio(struct bio *bio, int error)
 {
 	struct bbio *b = container_of(bio, struct bbio, bio);
 	struct closure *cl = bio->bi_private;
@@ -650,13 +630,113 @@ void bch_cache_read_endio(struct bio *bio, int error)
 	 */
 
 	if (error)
-		s->error = error;
-	else if (ptr_stale(s->op.c, &b->key, 0)) {
-		atomic_long_inc(&s->op.c->cache_read_races);
-		s->error = -EINTR;
+		s->iop.error = error;
+	else if (ptr_stale(s->iop.c, &b->key, 0)) {
+		atomic_long_inc(&s->iop.c->cache_read_races);
+		s->iop.error = -EINTR;
 	}
 
-	bch_bbio_endio(s->op.c, bio, error, "reading from cache");
+	bch_bbio_endio(s->iop.c, bio, error, "reading from cache");
+}
+
+/*
+ * Read from a single key, handling the initial cache miss if the key starts in
+ * the middle of the bio
+ */
+static int cache_lookup_fn(struct btree_op *op, struct btree *b, struct bkey *k)
+{
+	struct search *s = container_of(op, struct search, op);
+	struct bio *n, *bio = &s->bio.bio;
+	struct bkey *bio_key;
+	unsigned ptr;
+
+	if (bkey_cmp(k, &KEY(s->iop.inode, bio->bi_sector, 0)) <= 0)
+		return MAP_CONTINUE;
+
+	if (KEY_INODE(k) != s->iop.inode ||
+	    KEY_START(k) > bio->bi_sector) {
+		unsigned bio_sectors = bio_sectors(bio);
+		unsigned sectors = KEY_INODE(k) == s->iop.inode
+			? min_t(uint64_t, INT_MAX,
+				KEY_START(k) - bio->bi_sector)
+			: INT_MAX;
+
+		int ret = s->d->cache_miss(b, s, bio, sectors);
+		if (ret != MAP_CONTINUE)
+			return ret;
+
+		/* if this was a complete miss we shouldn't get here */
+		BUG_ON(bio_sectors <= sectors);
+	}
+
+	if (!KEY_SIZE(k))
+		return MAP_CONTINUE;
+
+	/* XXX: figure out best pointer - for multiple cache devices */
+	ptr = 0;
+
+	PTR_BUCKET(b->c, k, ptr)->prio = INITIAL_PRIO;
+
+	if (KEY_DIRTY(k))
+		s->read_dirty_data = true;
+
+	n = bch_bio_split(bio, min_t(uint64_t, INT_MAX,
+				     KEY_OFFSET(k) - bio->bi_sector),
+			  GFP_NOIO, s->d->bio_split);
+
+	bio_key = &container_of(n, struct bbio, bio)->key;
+	bch_bkey_copy_single_ptr(bio_key, k, ptr);
+
+	bch_cut_front(&KEY(s->iop.inode, n->bi_sector, 0), bio_key);
+	bch_cut_back(&KEY(s->iop.inode, bio_end_sector(n), 0), bio_key);
+
+	n->bi_end_io	= bch_cache_read_endio;
+	n->bi_private	= &s->cl;
+
+	/*
+	 * The bucket we're reading from might be reused while our bio
+	 * is in flight, and we could then end up reading the wrong
+	 * data.
+	 *
+	 * We guard against this by checking (in cache_read_endio()) if
+	 * the pointer is stale again; if so, we treat it as an error
+	 * and reread from the backing device (but we don't pass that
+	 * error up anywhere).
+	 */
+
+	__bch_submit_bbio(n, b->c);
+	return n == bio ? MAP_DONE : MAP_CONTINUE;
+}
+
+static void cache_lookup(struct closure *cl)
+{
+	struct search *s = container_of(cl, struct search, iop.cl);
+	struct bio *bio = &s->bio.bio;
+
+	int ret = bch_btree_map_keys(&s->op, s->iop.c,
+				     &KEY(s->iop.inode, bio->bi_sector, 0),
+				     cache_lookup_fn, MAP_END_KEY);
+	if (ret == -EAGAIN)
+		continue_at(cl, cache_lookup, bcache_wq);
+
+	closure_return(cl);
+}
+
+/* Common code for the make_request functions */
+
+static void request_endio(struct bio *bio, int error)
+{
+	struct closure *cl = bio->bi_private;
+
+	if (error) {
+		struct search *s = container_of(cl, struct search, cl);
+		s->iop.error = error;
+		/* Only cache read errors are recoverable */
+		s->recoverable = false;
+	}
+
+	bio_put(bio);
+	closure_put(cl);
 }
 
 static void bio_complete(struct search *s)
@@ -670,8 +750,8 @@ static void bio_complete(struct search *s)
 		part_stat_add(cpu, &s->d->disk->part0, ticks[rw], duration);
 		part_stat_unlock();
 
-		trace_bcache_request_end(s, s->orig_bio);
-		bio_endio(s->orig_bio, s->error);
+		trace_bcache_request_end(s->d, s->orig_bio);
+		bio_endio(s->orig_bio, s->iop.error);
 		s->orig_bio = NULL;
 	}
 }
@@ -691,8 +771,8 @@ static void search_free(struct closure *cl)
 	struct search *s = container_of(cl, struct search, cl);
 	bio_complete(s);
 
-	if (s->op.cache_bio)
-		bio_put(s->op.cache_bio);
+	if (s->iop.bio)
+		bio_put(s->iop.bio);
 
 	if (s->unaligned_bvec)
 		mempool_free(s->bio.bio.bi_io_vec, s->d->unaligned_bvec);
@@ -703,21 +783,22 @@ static void search_free(struct closure *cl)
 
 static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
 {
+	struct search *s;
 	struct bio_vec *bv;
-	struct search *s = mempool_alloc(d->c->search, GFP_NOIO);
-	memset(s, 0, offsetof(struct search, op.keys));
+
+	s = mempool_alloc(d->c->search, GFP_NOIO);
+	memset(s, 0, offsetof(struct search, iop.insert_keys));
 
 	__closure_init(&s->cl, NULL);
 
-	s->op.inode		= d->id;
-	s->op.c			= d->c;
+	s->iop.inode		= d->id;
+	s->iop.c		= d->c;
 	s->d			= d;
 	s->op.lock		= -1;
-	s->task			= current;
+	s->iop.write_point	= hash_long((unsigned long) current, 16);
 	s->orig_bio		= bio;
 	s->write		= (bio->bi_rw & REQ_WRITE) != 0;
-	s->op.flush_journal	= (bio->bi_rw & (REQ_FLUSH|REQ_FUA)) != 0;
-	s->op.skip		= (bio->bi_rw & REQ_DISCARD) != 0;
+	s->iop.flush_journal	= (bio->bi_rw & (REQ_FLUSH|REQ_FUA)) != 0;
 	s->recoverable		= 1;
 	s->start_time		= jiffies;
 	do_bio_hook(s);
@@ -734,18 +815,6 @@ static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
 	return s;
 }
 
-static void btree_read_async(struct closure *cl)
-{
-	struct btree_op *op = container_of(cl, struct btree_op, cl);
-
-	int ret = btree_root(search_recurse, op->c, op);
-
-	if (ret == -EAGAIN)
-		continue_at(cl, btree_read_async, bcache_wq);
-
-	closure_return(cl);
-}
-
 /* Cached devices */
 
 static void cached_dev_bio_complete(struct closure *cl)
@@ -759,27 +828,28 @@ static void cached_dev_bio_complete(struct closure *cl)
 
 /* Process reads */
 
-static void cached_dev_read_complete(struct closure *cl)
+static void cached_dev_cache_miss_done(struct closure *cl)
 {
 	struct search *s = container_of(cl, struct search, cl);
 
-	if (s->op.insert_collision)
-		bch_mark_cache_miss_collision(s);
+	if (s->iop.replace_collision)
+		bch_mark_cache_miss_collision(s->iop.c, s->d);
 
-	if (s->op.cache_bio) {
+	if (s->iop.bio) {
 		int i;
 		struct bio_vec *bv;
 
-		__bio_for_each_segment(bv, s->op.cache_bio, i, 0)
+		bio_for_each_segment_all(bv, s->iop.bio, i)
 			__free_page(bv->bv_page);
 	}
 
 	cached_dev_bio_complete(cl);
 }
 
-static void request_read_error(struct closure *cl)
+static void cached_dev_read_error(struct closure *cl)
 {
 	struct search *s = container_of(cl, struct search, cl);
+	struct bio *bio = &s->bio.bio;
 	struct bio_vec *bv;
 	int i;
 
@@ -787,7 +857,7 @@ static void request_read_error(struct closure *cl)
 		/* Retry from the backing device: */
 		trace_bcache_read_retry(s->orig_bio);
 
-		s->error = 0;
+		s->iop.error = 0;
 		bv = s->bio.bio.bi_io_vec;
 		do_bio_hook(s);
 		s->bio.bio.bi_io_vec = bv;
@@ -803,146 +873,148 @@ static void request_read_error(struct closure *cl)
 
 		/* XXX: invalidate cache */
 
-		closure_bio_submit(&s->bio.bio, &s->cl, s->d);
+		closure_bio_submit(bio, cl, s->d);
 	}
 
-	continue_at(cl, cached_dev_read_complete, NULL);
+	continue_at(cl, cached_dev_cache_miss_done, NULL);
 }
 
-static void request_read_done(struct closure *cl)
+static void cached_dev_read_done(struct closure *cl)
 {
 	struct search *s = container_of(cl, struct search, cl);
 	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 
 	/*
-	 * s->cache_bio != NULL implies that we had a cache miss; cache_bio now
-	 * contains data ready to be inserted into the cache.
+	 * We had a cache miss; cache_bio now contains data ready to be inserted
+	 * into the cache.
 	 *
 	 * First, we copy the data we just read from cache_bio's bounce buffers
 	 * to the buffers the original bio pointed to:
 	 */
 
-	if (s->op.cache_bio) {
-		bio_reset(s->op.cache_bio);
-		s->op.cache_bio->bi_sector	= s->cache_miss->bi_sector;
-		s->op.cache_bio->bi_bdev	= s->cache_miss->bi_bdev;
-		s->op.cache_bio->bi_size	= s->cache_bio_sectors << 9;
-		bch_bio_map(s->op.cache_bio, NULL);
+	if (s->iop.bio) {
+		bio_reset(s->iop.bio);
+		s->iop.bio->bi_sector = s->cache_miss->bi_sector;
+		s->iop.bio->bi_bdev = s->cache_miss->bi_bdev;
+		s->iop.bio->bi_size = s->insert_bio_sectors << 9;
+		bch_bio_map(s->iop.bio, NULL);
 
-		bio_copy_data(s->cache_miss, s->op.cache_bio);
+		bio_copy_data(s->cache_miss, s->iop.bio);
 
 		bio_put(s->cache_miss);
 		s->cache_miss = NULL;
 	}
 
-	if (verify(dc, &s->bio.bio) && s->recoverable)
-		bch_data_verify(s);
+	if (verify(dc, &s->bio.bio) && s->recoverable &&
+	    !s->unaligned_bvec && !s->read_dirty_data)
+		bch_data_verify(dc, s->orig_bio);
 
 	bio_complete(s);
 
-	if (s->op.cache_bio &&
-	    !test_bit(CACHE_SET_STOPPING, &s->op.c->flags)) {
-		s->op.type = BTREE_REPLACE;
-		closure_call(&s->op.cl, bch_insert_data, NULL, cl);
+	if (s->iop.bio &&
+	    !test_bit(CACHE_SET_STOPPING, &s->iop.c->flags)) {
+		BUG_ON(!s->iop.replace);
+		closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
 	}
 
-	continue_at(cl, cached_dev_read_complete, NULL);
+	continue_at(cl, cached_dev_cache_miss_done, NULL);
 }
 
-static void request_read_done_bh(struct closure *cl)
+static void cached_dev_read_done_bh(struct closure *cl)
 {
 	struct search *s = container_of(cl, struct search, cl);
 	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 
-	bch_mark_cache_accounting(s, !s->cache_miss, s->op.skip);
-	trace_bcache_read(s->orig_bio, !s->cache_miss, s->op.skip);
+	bch_mark_cache_accounting(s->iop.c, s->d,
+				  !s->cache_miss, s->iop.bypass);
+	trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass);
 
-	if (s->error)
-		continue_at_nobarrier(cl, request_read_error, bcache_wq);
-	else if (s->op.cache_bio || verify(dc, &s->bio.bio))
-		continue_at_nobarrier(cl, request_read_done, bcache_wq);
+	if (s->iop.error)
+		continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq);
+	else if (s->iop.bio || verify(dc, &s->bio.bio))
+		continue_at_nobarrier(cl, cached_dev_read_done, bcache_wq);
 	else
-		continue_at_nobarrier(cl, cached_dev_read_complete, NULL);
+		continue_at_nobarrier(cl, cached_dev_bio_complete, NULL);
 }
 
 static int cached_dev_cache_miss(struct btree *b, struct search *s,
 				 struct bio *bio, unsigned sectors)
 {
-	int ret = 0;
-	unsigned reada;
+	int ret = MAP_CONTINUE;
+	unsigned reada = 0;
 	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
-	struct bio *miss;
-
-	miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
-	if (miss == bio)
-		s->op.lookup_done = true;
+	struct bio *miss, *cache_bio;
 
-	miss->bi_end_io		= request_endio;
-	miss->bi_private	= &s->cl;
-
-	if (s->cache_miss || s->op.skip)
+	if (s->cache_miss || s->iop.bypass) {
+		miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
+		ret = miss == bio ? MAP_DONE : MAP_CONTINUE;
 		goto out_submit;
-
-	if (miss != bio ||
-	    (bio->bi_rw & REQ_RAHEAD) ||
-	    (bio->bi_rw & REQ_META) ||
-	    s->op.c->gc_stats.in_use >= CUTOFF_CACHE_READA)
-		reada = 0;
-	else {
-		reada = min(dc->readahead >> 9,
-			    sectors - bio_sectors(miss));
-
-		if (bio_end_sector(miss) + reada > bdev_sectors(miss->bi_bdev))
-			reada = bdev_sectors(miss->bi_bdev) -
-				bio_end_sector(miss);
 	}
 
-	s->cache_bio_sectors = bio_sectors(miss) + reada;
-	s->op.cache_bio = bio_alloc_bioset(GFP_NOWAIT,
-			DIV_ROUND_UP(s->cache_bio_sectors, PAGE_SECTORS),
-			dc->disk.bio_split);
+	if (!(bio->bi_rw & REQ_RAHEAD) &&
+	    !(bio->bi_rw & REQ_META) &&
+	    s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA)
+		reada = min_t(sector_t, dc->readahead >> 9,
+			      bdev_sectors(bio->bi_bdev) - bio_end_sector(bio));
 
-	if (!s->op.cache_bio)
-		goto out_submit;
+	s->insert_bio_sectors = min(sectors, bio_sectors(bio) + reada);
 
-	s->op.cache_bio->bi_sector	= miss->bi_sector;
-	s->op.cache_bio->bi_bdev	= miss->bi_bdev;
-	s->op.cache_bio->bi_size	= s->cache_bio_sectors << 9;
+	s->iop.replace_key = KEY(s->iop.inode,
+				 bio->bi_sector + s->insert_bio_sectors,
+				 s->insert_bio_sectors);
 
-	s->op.cache_bio->bi_end_io	= request_endio;
-	s->op.cache_bio->bi_private	= &s->cl;
+	ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key);
+	if (ret)
+		return ret;
+
+	s->iop.replace = true;
+
+	miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split);
 
 	/* btree_search_recurse()'s btree iterator is no good anymore */
-	ret = -EINTR;
-	if (!bch_btree_insert_check_key(b, &s->op, s->op.cache_bio))
-		goto out_put;
+	ret = miss == bio ? MAP_DONE : -EINTR;
+
+	cache_bio = bio_alloc_bioset(GFP_NOWAIT,
+			DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS),
+			dc->disk.bio_split);
+	if (!cache_bio)
+		goto out_submit;
+
+	cache_bio->bi_sector	= miss->bi_sector;
+	cache_bio->bi_bdev	= miss->bi_bdev;
+	cache_bio->bi_size	= s->insert_bio_sectors << 9;
+
+	cache_bio->bi_end_io	= request_endio;
+	cache_bio->bi_private	= &s->cl;
 
-	bch_bio_map(s->op.cache_bio, NULL);
-	if (bio_alloc_pages(s->op.cache_bio, __GFP_NOWARN|GFP_NOIO))
+	bch_bio_map(cache_bio, NULL);
+	if (bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
 		goto out_put;
 
-	s->cache_miss = miss;
-	bio_get(s->op.cache_bio);
+	if (reada)
+		bch_mark_cache_readahead(s->iop.c, s->d);
 
-	closure_bio_submit(s->op.cache_bio, &s->cl, s->d);
+	s->cache_miss	= miss;
+	s->iop.bio	= cache_bio;
+	bio_get(cache_bio);
+	closure_bio_submit(cache_bio, &s->cl, s->d);
 
 	return ret;
 out_put:
-	bio_put(s->op.cache_bio);
-	s->op.cache_bio = NULL;
+	bio_put(cache_bio);
 out_submit:
+	miss->bi_end_io		= request_endio;
+	miss->bi_private	= &s->cl;
 	closure_bio_submit(miss, &s->cl, s->d);
 	return ret;
 }
 
-static void request_read(struct cached_dev *dc, struct search *s)
+static void cached_dev_read(struct cached_dev *dc, struct search *s)
 {
 	struct closure *cl = &s->cl;
 
-	check_should_skip(dc, s);
-	closure_call(&s->op.cl, btree_read_async, NULL, cl);
-
-	continue_at(cl, request_read_done_bh, NULL);
+	closure_call(&s->iop.cl, cache_lookup, NULL, cl);
+	continue_at(cl, cached_dev_read_done_bh, NULL);
 }
 
 /* Process writes */
@@ -956,47 +1028,52 @@ static void cached_dev_write_complete(struct closure *cl)
 	cached_dev_bio_complete(cl);
 }
 
-static void request_write(struct cached_dev *dc, struct search *s)
+static void cached_dev_write(struct cached_dev *dc, struct search *s)
 {
 	struct closure *cl = &s->cl;
 	struct bio *bio = &s->bio.bio;
-	struct bkey start, end;
-	start = KEY(dc->disk.id, bio->bi_sector, 0);
-	end = KEY(dc->disk.id, bio_end_sector(bio), 0);
+	struct bkey start = KEY(dc->disk.id, bio->bi_sector, 0);
+	struct bkey end = KEY(dc->disk.id, bio_end_sector(bio), 0);
 
-	bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys, &start, &end);
+	bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys, &start, &end);
 
-	check_should_skip(dc, s);
 	down_read_non_owner(&dc->writeback_lock);
-
 	if (bch_keybuf_check_overlapping(&dc->writeback_keys, &start, &end)) {
-		s->op.skip	= false;
-		s->writeback	= true;
+		/*
+		 * We overlap with some dirty data undergoing background
+		 * writeback, force this write to writeback
+		 */
+		s->iop.bypass = false;
+		s->iop.writeback = true;
 	}
 
+	/*
+	 * Discards aren't _required_ to do anything, so skipping if
+	 * check_overlapping returned true is ok
+	 *
+	 * But check_overlapping drops dirty keys for which io hasn't started,
+	 * so we still want to call it.
+	 */
 	if (bio->bi_rw & REQ_DISCARD)
-		goto skip;
+		s->iop.bypass = true;
 
 	if (should_writeback(dc, s->orig_bio,
 			     cache_mode(dc, bio),
-			     s->op.skip)) {
-		s->op.skip = false;
-		s->writeback = true;
+			     s->iop.bypass)) {
+		s->iop.bypass = false;
+		s->iop.writeback = true;
 	}
 
-	if (s->op.skip)
-		goto skip;
-
-	trace_bcache_write(s->orig_bio, s->writeback, s->op.skip);
+	if (s->iop.bypass) {
+		s->iop.bio = s->orig_bio;
+		bio_get(s->iop.bio);
 
-	if (!s->writeback) {
-		s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO,
-						   dc->disk.bio_split);
-
-		closure_bio_submit(bio, cl, s->d);
-	} else {
+		if (!(bio->bi_rw & REQ_DISCARD) ||
+		    blk_queue_discard(bdev_get_queue(dc->bdev)))
+			closure_bio_submit(bio, cl, s->d);
+	} else if (s->iop.writeback) {
 		bch_writeback_add(dc);
-		s->op.cache_bio = bio;
+		s->iop.bio = bio;
 
 		if (bio->bi_rw & REQ_FLUSH) {
 			/* Also need to send a flush to the backing device */
@@ -1010,36 +1087,26 @@ static void request_write(struct cached_dev *dc, struct search *s)
 
 			closure_bio_submit(flush, cl, s->d);
 		}
-	}
-out:
-	closure_call(&s->op.cl, bch_insert_data, NULL, cl);
-	continue_at(cl, cached_dev_write_complete, NULL);
-skip:
-	s->op.skip = true;
-	s->op.cache_bio = s->orig_bio;
-	bio_get(s->op.cache_bio);
+	} else {
+		s->iop.bio = bio_clone_bioset(bio, GFP_NOIO,
+					      dc->disk.bio_split);
 
-	if ((bio->bi_rw & REQ_DISCARD) &&
-	    !blk_queue_discard(bdev_get_queue(dc->bdev)))
-		goto out;
+		closure_bio_submit(bio, cl, s->d);
+	}
 
-	closure_bio_submit(bio, cl, s->d);
-	goto out;
+	closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
+	continue_at(cl, cached_dev_write_complete, NULL);
 }
 
-static void request_nodata(struct cached_dev *dc, struct search *s)
+static void cached_dev_nodata(struct closure *cl)
 {
-	struct closure *cl = &s->cl;
+	struct search *s = container_of(cl, struct search, cl);
 	struct bio *bio = &s->bio.bio;
 
-	if (bio->bi_rw & REQ_DISCARD) {
-		request_write(dc, s);
-		return;
-	}
-
-	if (s->op.flush_journal)
-		bch_journal_meta(s->op.c, cl);
+	if (s->iop.flush_journal)
+		bch_journal_meta(s->iop.c, cl);
 
+	/* If it's a flush, we send the flush to the backing device too */
 	closure_bio_submit(bio, cl, s->d);
 
 	continue_at(cl, cached_dev_bio_complete, NULL);
@@ -1047,134 +1114,6 @@ static void request_nodata(struct cached_dev *dc, struct search *s)
 
 /* Cached devices - read & write stuff */
 
-unsigned bch_get_congested(struct cache_set *c)
-{
-	int i;
-	long rand;
-
-	if (!c->congested_read_threshold_us &&
-	    !c->congested_write_threshold_us)
-		return 0;
-
-	i = (local_clock_us() - c->congested_last_us) / 1024;
-	if (i < 0)
-		return 0;
-
-	i += atomic_read(&c->congested);
-	if (i >= 0)
-		return 0;
-
-	i += CONGESTED_MAX;
-
-	if (i > 0)
-		i = fract_exp_two(i, 6);
-
-	rand = get_random_int();
-	i -= bitmap_weight(&rand, BITS_PER_LONG);
-
-	return i > 0 ? i : 1;
-}
-
-static void add_sequential(struct task_struct *t)
-{
-	ewma_add(t->sequential_io_avg,
-		 t->sequential_io, 8, 0);
-
-	t->sequential_io = 0;
-}
-
-static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k)
-{
-	return &dc->io_hash[hash_64(k, RECENT_IO_BITS)];
-}
-
-static void check_should_skip(struct cached_dev *dc, struct search *s)
-{
-	struct cache_set *c = s->op.c;
-	struct bio *bio = &s->bio.bio;
-	unsigned mode = cache_mode(dc, bio);
-	unsigned sectors, congested = bch_get_congested(c);
-
-	if (atomic_read(&dc->disk.detaching) ||
-	    c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
-	    (bio->bi_rw & REQ_DISCARD))
-		goto skip;
-
-	if (mode == CACHE_MODE_NONE ||
-	    (mode == CACHE_MODE_WRITEAROUND &&
-	     (bio->bi_rw & REQ_WRITE)))
-		goto skip;
-
-	if (bio->bi_sector   & (c->sb.block_size - 1) ||
-	    bio_sectors(bio) & (c->sb.block_size - 1)) {
-		pr_debug("skipping unaligned io");
-		goto skip;
-	}
-
-	if (!congested && !dc->sequential_cutoff)
-		goto rescale;
-
-	if (!congested &&
-	    mode == CACHE_MODE_WRITEBACK &&
-	    (bio->bi_rw & REQ_WRITE) &&
-	    (bio->bi_rw & REQ_SYNC))
-		goto rescale;
-
-	if (dc->sequential_merge) {
-		struct io *i;
-
-		spin_lock(&dc->io_lock);
-
-		hlist_for_each_entry(i, iohash(dc, bio->bi_sector), hash)
-			if (i->last == bio->bi_sector &&
-			    time_before(jiffies, i->jiffies))
-				goto found;
-
-		i = list_first_entry(&dc->io_lru, struct io, lru);
-
-		add_sequential(s->task);
-		i->sequential = 0;
-found:
-		if (i->sequential + bio->bi_size > i->sequential)
-			i->sequential	+= bio->bi_size;
-
-		i->last			 = bio_end_sector(bio);
-		i->jiffies		 = jiffies + msecs_to_jiffies(5000);
-		s->task->sequential_io	 = i->sequential;
-
-		hlist_del(&i->hash);
-		hlist_add_head(&i->hash, iohash(dc, i->last));
-		list_move_tail(&i->lru, &dc->io_lru);
-
-		spin_unlock(&dc->io_lock);
-	} else {
-		s->task->sequential_io = bio->bi_size;
-
-		add_sequential(s->task);
-	}
-
-	sectors = max(s->task->sequential_io,
-		      s->task->sequential_io_avg) >> 9;
-
-	if (dc->sequential_cutoff &&
-	    sectors >= dc->sequential_cutoff >> 9) {
-		trace_bcache_bypass_sequential(s->orig_bio);
-		goto skip;
-	}
-
-	if (congested && sectors >= congested) {
-		trace_bcache_bypass_congested(s->orig_bio);
-		goto skip;
-	}
-
-rescale:
-	bch_rescale_priorities(c, bio_sectors(bio));
-	return;
-skip:
-	bch_mark_sectors_bypassed(s, bio_sectors(bio));
-	s->op.skip = true;
-}
-
 static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
 {
 	struct search *s;
@@ -1192,14 +1131,24 @@ static void cached_dev_make_request(struct request_queue *q, struct bio *bio)
 
 	if (cached_dev_get(dc)) {
 		s = search_alloc(bio, d);
-		trace_bcache_request_start(s, bio);
-
-		if (!bio_has_data(bio))
-			request_nodata(dc, s);
-		else if (rw)
-			request_write(dc, s);
-		else
-			request_read(dc, s);
+		trace_bcache_request_start(s->d, bio);
+
+		if (!bio->bi_size) {
+			/*
+			 * can't call bch_journal_meta from under
+			 * generic_make_request
+			 */
+			continue_at_nobarrier(&s->cl,
+					      cached_dev_nodata,
+					      bcache_wq);
+		} else {
+			s->iop.bypass = check_should_bypass(dc, bio);
+
+			if (rw)
+				cached_dev_write(dc, s);
+			else
+				cached_dev_read(dc, s);
+		}
 	} else {
 		if ((bio->bi_rw & REQ_DISCARD) &&
 		    !blk_queue_discard(bdev_get_queue(dc->bdev)))
@@ -1274,9 +1223,19 @@ static int flash_dev_cache_miss(struct btree *b, struct search *s,
 	bio_advance(bio, min(sectors << 9, bio->bi_size));
 
 	if (!bio->bi_size)
-		s->op.lookup_done = true;
+		return MAP_DONE;
 
-	return 0;
+	return MAP_CONTINUE;
+}
+
+static void flash_dev_nodata(struct closure *cl)
+{
+	struct search *s = container_of(cl, struct search, cl);
+
+	if (s->iop.flush_journal)
+		bch_journal_meta(s->iop.c, cl);
+
+	continue_at(cl, search_free, NULL);
 }
 
 static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
@@ -1295,23 +1254,28 @@ static void flash_dev_make_request(struct request_queue *q, struct bio *bio)
 	cl = &s->cl;
 	bio = &s->bio.bio;
 
-	trace_bcache_request_start(s, bio);
+	trace_bcache_request_start(s->d, bio);
 
-	if (bio_has_data(bio) && !rw) {
-		closure_call(&s->op.cl, btree_read_async, NULL, cl);
-	} else if (bio_has_data(bio) || s->op.skip) {
-		bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys,
+	if (!bio->bi_size) {
+		/*
+		 * can't call bch_journal_meta from under
+		 * generic_make_request
+		 */
+		continue_at_nobarrier(&s->cl,
+				      flash_dev_nodata,
+				      bcache_wq);
+	} else if (rw) {
+		bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys,
 					&KEY(d->id, bio->bi_sector, 0),
 					&KEY(d->id, bio_end_sector(bio), 0));
 
-		s->writeback	= true;
-		s->op.cache_bio	= bio;
+		s->iop.bypass		= (bio->bi_rw & REQ_DISCARD) != 0;
+		s->iop.writeback	= true;
+		s->iop.bio		= bio;
 
-		closure_call(&s->op.cl, bch_insert_data, NULL, cl);
+		closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
 	} else {
-		/* No data - probably a cache flush */
-		if (s->op.flush_journal)
-			bch_journal_meta(s->op.c, cl);
+		closure_call(&s->iop.cl, cache_lookup, NULL, cl);
 	}
 
 	continue_at(cl, search_free, NULL);
diff --git a/drivers/md/bcache/request.h b/drivers/md/bcache/request.h
index 57dc4784f4f4..2cd65bf073c2 100644
--- a/drivers/md/bcache/request.h
+++ b/drivers/md/bcache/request.h
@@ -3,40 +3,33 @@
 
 #include <linux/cgroup.h>
 
-struct search {
-	/* Stack frame for bio_complete */
+struct data_insert_op {
 	struct closure		cl;
+	struct cache_set	*c;
+	struct bio		*bio;
 
-	struct bcache_device	*d;
-	struct task_struct	*task;
-
-	struct bbio		bio;
-	struct bio		*orig_bio;
-	struct bio		*cache_miss;
-	unsigned		cache_bio_sectors;
-
-	unsigned		recoverable:1;
-	unsigned		unaligned_bvec:1;
+	unsigned		inode;
+	uint16_t		write_point;
+	uint16_t		write_prio;
+	short			error;
 
-	unsigned		write:1;
+	unsigned		bypass:1;
 	unsigned		writeback:1;
+	unsigned		flush_journal:1;
+	unsigned		csum:1;
 
-	/* IO error returned to s->bio */
-	short			error;
-	unsigned long		start_time;
+	unsigned		replace:1;
+	unsigned		replace_collision:1;
+
+	unsigned		insert_data_done:1;
 
-	/* Anything past op->keys won't get zeroed in do_bio_hook */
-	struct btree_op		op;
+	/* Anything past this point won't get zeroed in search_alloc() */
+	struct keylist		insert_keys;
+	BKEY_PADDED(replace_key);
 };
 
-void bch_cache_read_endio(struct bio *, int);
 unsigned bch_get_congested(struct cache_set *);
-void bch_insert_data(struct closure *cl);
-void bch_btree_insert_async(struct closure *);
-void bch_cache_read_endio(struct bio *, int);
-
-void bch_open_buckets_free(struct cache_set *);
-int bch_open_buckets_alloc(struct cache_set *);
+void bch_data_insert(struct closure *cl);
 
 void bch_cached_dev_request_init(struct cached_dev *dc);
 void bch_flash_dev_request_init(struct bcache_device *d);
diff --git a/drivers/md/bcache/stats.c b/drivers/md/bcache/stats.c
index b8730e714d69..84d0782f702e 100644
--- a/drivers/md/bcache/stats.c
+++ b/drivers/md/bcache/stats.c
@@ -7,7 +7,6 @@
 #include "bcache.h"
 #include "stats.h"
 #include "btree.h"
-#include "request.h"
 #include "sysfs.h"
 
 /*
@@ -196,35 +195,36 @@ static void mark_cache_stats(struct cache_stat_collector *stats,
 			atomic_inc(&stats->cache_bypass_misses);
 }
 
-void bch_mark_cache_accounting(struct search *s, bool hit, bool bypass)
+void bch_mark_cache_accounting(struct cache_set *c, struct bcache_device *d,
+			       bool hit, bool bypass)
 {
-	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+	struct cached_dev *dc = container_of(d, struct cached_dev, disk);
 	mark_cache_stats(&dc->accounting.collector, hit, bypass);
-	mark_cache_stats(&s->op.c->accounting.collector, hit, bypass);
+	mark_cache_stats(&c->accounting.collector, hit, bypass);
 #ifdef CONFIG_CGROUP_BCACHE
 	mark_cache_stats(&(bch_bio_to_cgroup(s->orig_bio)->stats), hit, bypass);
 #endif
 }
 
-void bch_mark_cache_readahead(struct search *s)
+void bch_mark_cache_readahead(struct cache_set *c, struct bcache_device *d)
 {
-	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+	struct cached_dev *dc = container_of(d, struct cached_dev, disk);
 	atomic_inc(&dc->accounting.collector.cache_readaheads);
-	atomic_inc(&s->op.c->accounting.collector.cache_readaheads);
+	atomic_inc(&c->accounting.collector.cache_readaheads);
 }
 
-void bch_mark_cache_miss_collision(struct search *s)
+void bch_mark_cache_miss_collision(struct cache_set *c, struct bcache_device *d)
 {
-	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
+	struct cached_dev *dc = container_of(d, struct cached_dev, disk);
 	atomic_inc(&dc->accounting.collector.cache_miss_collisions);
-	atomic_inc(&s->op.c->accounting.collector.cache_miss_collisions);
+	atomic_inc(&c->accounting.collector.cache_miss_collisions);
 }
 
-void bch_mark_sectors_bypassed(struct search *s, int sectors)
+void bch_mark_sectors_bypassed(struct cache_set *c, struct cached_dev *dc,
+			       int sectors)
 {
-	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 	atomic_add(sectors, &dc->accounting.collector.sectors_bypassed);
-	atomic_add(sectors, &s->op.c->accounting.collector.sectors_bypassed);
+	atomic_add(sectors, &c->accounting.collector.sectors_bypassed);
 }
 
 void bch_cache_accounting_init(struct cache_accounting *acc,
diff --git a/drivers/md/bcache/stats.h b/drivers/md/bcache/stats.h
index c7c7a8fd29fe..adbff141c887 100644
--- a/drivers/md/bcache/stats.h
+++ b/drivers/md/bcache/stats.h
@@ -38,7 +38,9 @@ struct cache_accounting {
 	struct cache_stats day;
 };
 
-struct search;
+struct cache_set;
+struct cached_dev;
+struct bcache_device;
 
 void bch_cache_accounting_init(struct cache_accounting *acc,
 			       struct closure *parent);
@@ -50,9 +52,10 @@ void bch_cache_accounting_clear(struct cache_accounting *acc);
 
 void bch_cache_accounting_destroy(struct cache_accounting *acc);
 
-void bch_mark_cache_accounting(struct search *s, bool hit, bool bypass);
-void bch_mark_cache_readahead(struct search *s);
-void bch_mark_cache_miss_collision(struct search *s);
-void bch_mark_sectors_bypassed(struct search *s, int sectors);
+void bch_mark_cache_accounting(struct cache_set *, struct bcache_device *,
+			       bool, bool);
+void bch_mark_cache_readahead(struct cache_set *, struct bcache_device *);
+void bch_mark_cache_miss_collision(struct cache_set *, struct bcache_device *);
+void bch_mark_sectors_bypassed(struct cache_set *, struct cached_dev *, int);
 
 #endif /* _BCACHE_STATS_H_ */
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 547c4c57b052..dec15cd2d797 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -16,6 +16,7 @@
 #include <linux/buffer_head.h>
 #include <linux/debugfs.h>
 #include <linux/genhd.h>
+#include <linux/idr.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/random.h>
@@ -45,21 +46,13 @@ const char * const bch_cache_modes[] = {
 	NULL
 };
 
-struct uuid_entry_v0 {
-	uint8_t		uuid[16];
-	uint8_t		label[32];
-	uint32_t	first_reg;
-	uint32_t	last_reg;
-	uint32_t	invalidated;
-	uint32_t	pad;
-};
-
 static struct kobject *bcache_kobj;
 struct mutex bch_register_lock;
 LIST_HEAD(bch_cache_sets);
 static LIST_HEAD(uncached_devices);
 
-static int bcache_major, bcache_minor;
+static int bcache_major;
+static DEFINE_IDA(bcache_minor);
 static wait_queue_head_t unregister_wait;
 struct workqueue_struct *bcache_wq;
 
@@ -382,7 +375,7 @@ static char *uuid_read(struct cache_set *c, struct jset *j, struct closure *cl)
 {
 	struct bkey *k = &j->uuid_bucket;
 
-	if (__bch_ptr_invalid(c, 1, k))
+	if (bch_btree_ptr_invalid(c, k))
 		return "bad uuid pointer";
 
 	bkey_copy(&c->uuid_bucket, k);
@@ -427,7 +420,7 @@ static int __uuid_write(struct cache_set *c)
 
 	lockdep_assert_held(&bch_register_lock);
 
-	if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, &cl))
+	if (bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, true))
 		return 1;
 
 	SET_KEY_SIZE(&k.key, c->sb.bucket_size);
@@ -435,7 +428,7 @@ static int __uuid_write(struct cache_set *c)
 	closure_sync(&cl);
 
 	bkey_copy(&c->uuid_bucket, &k.key);
-	__bkey_put(c, &k.key);
+	bkey_put(c, &k.key);
 	return 0;
 }
 
@@ -562,10 +555,10 @@ void bch_prio_write(struct cache *ca)
 		}
 
 		p->next_bucket	= ca->prio_buckets[i + 1];
-		p->magic	= pset_magic(ca);
+		p->magic	= pset_magic(&ca->sb);
 		p->csum		= bch_crc64(&p->magic, bucket_bytes(ca) - 8);
 
-		bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, &cl);
+		bucket = bch_bucket_alloc(ca, WATERMARK_PRIO, true);
 		BUG_ON(bucket == -1);
 
 		mutex_unlock(&ca->set->bucket_lock);
@@ -613,7 +606,7 @@ static void prio_read(struct cache *ca, uint64_t bucket)
 			if (p->csum != bch_crc64(&p->magic, bucket_bytes(ca) - 8))
 				pr_warn("bad csum reading priorities");
 
-			if (p->magic != pset_magic(ca))
+			if (p->magic != pset_magic(&ca->sb))
 				pr_warn("bad magic reading priorities");
 
 			bucket = p->next_bucket;
@@ -630,7 +623,7 @@ static void prio_read(struct cache *ca, uint64_t bucket)
 static int open_dev(struct block_device *b, fmode_t mode)
 {
 	struct bcache_device *d = b->bd_disk->private_data;
-	if (atomic_read(&d->closing))
+	if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
 		return -ENXIO;
 
 	closure_get(&d->cl);
@@ -659,20 +652,24 @@ static const struct block_device_operations bcache_ops = {
 
 void bcache_device_stop(struct bcache_device *d)
 {
-	if (!atomic_xchg(&d->closing, 1))
+	if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
 		closure_queue(&d->cl);
 }
 
 static void bcache_device_unlink(struct bcache_device *d)
 {
-	unsigned i;
-	struct cache *ca;
+	lockdep_assert_held(&bch_register_lock);
 
-	sysfs_remove_link(&d->c->kobj, d->name);
-	sysfs_remove_link(&d->kobj, "cache");
+	if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
+		unsigned i;
+		struct cache *ca;
 
-	for_each_cache(ca, d->c, i)
-		bd_unlink_disk_holder(ca->bdev, d->disk);
+		sysfs_remove_link(&d->c->kobj, d->name);
+		sysfs_remove_link(&d->kobj, "cache");
+
+		for_each_cache(ca, d->c, i)
+			bd_unlink_disk_holder(ca->bdev, d->disk);
+	}
 }
 
 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
@@ -696,19 +693,16 @@ static void bcache_device_detach(struct bcache_device *d)
 {
 	lockdep_assert_held(&bch_register_lock);
 
-	if (atomic_read(&d->detaching)) {
+	if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
 		struct uuid_entry *u = d->c->uuids + d->id;
 
 		SET_UUID_FLASH_ONLY(u, 0);
 		memcpy(u->uuid, invalid_uuid, 16);
 		u->invalidated = cpu_to_le32(get_seconds());
 		bch_uuid_write(d->c);
-
-		atomic_set(&d->detaching, 0);
 	}
 
-	if (!d->flush_done)
-		bcache_device_unlink(d);
+	bcache_device_unlink(d);
 
 	d->c->devices[d->id] = NULL;
 	closure_put(&d->c->caching);
@@ -739,14 +733,20 @@ static void bcache_device_free(struct bcache_device *d)
 		del_gendisk(d->disk);
 	if (d->disk && d->disk->queue)
 		blk_cleanup_queue(d->disk->queue);
-	if (d->disk)
+	if (d->disk) {
+		ida_simple_remove(&bcache_minor, d->disk->first_minor);
 		put_disk(d->disk);
+	}
 
 	bio_split_pool_free(&d->bio_split_hook);
 	if (d->unaligned_bvec)
 		mempool_destroy(d->unaligned_bvec);
 	if (d->bio_split)
 		bioset_free(d->bio_split);
+	if (is_vmalloc_addr(d->full_dirty_stripes))
+		vfree(d->full_dirty_stripes);
+	else
+		kfree(d->full_dirty_stripes);
 	if (is_vmalloc_addr(d->stripe_sectors_dirty))
 		vfree(d->stripe_sectors_dirty);
 	else
@@ -760,15 +760,19 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 {
 	struct request_queue *q;
 	size_t n;
+	int minor;
 
-	if (!d->stripe_size_bits)
-		d->stripe_size_bits = 31;
+	if (!d->stripe_size)
+		d->stripe_size = 1 << 31;
 
-	d->nr_stripes = round_up(sectors, 1 << d->stripe_size_bits) >>
-		d->stripe_size_bits;
+	d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
 
-	if (!d->nr_stripes || d->nr_stripes > SIZE_MAX / sizeof(atomic_t))
+	if (!d->nr_stripes ||
+	    d->nr_stripes > INT_MAX ||
+	    d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) {
+		pr_err("nr_stripes too large");
 		return -ENOMEM;
+	}
 
 	n = d->nr_stripes * sizeof(atomic_t);
 	d->stripe_sectors_dirty = n < PAGE_SIZE << 6
@@ -777,22 +781,38 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 	if (!d->stripe_sectors_dirty)
 		return -ENOMEM;
 
+	n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
+	d->full_dirty_stripes = n < PAGE_SIZE << 6
+		? kzalloc(n, GFP_KERNEL)
+		: vzalloc(n);
+	if (!d->full_dirty_stripes)
+		return -ENOMEM;
+
+	minor = ida_simple_get(&bcache_minor, 0, MINORMASK + 1, GFP_KERNEL);
+	if (minor < 0)
+		return minor;
+
 	if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
 	    !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
 				sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
 	    bio_split_pool_init(&d->bio_split_hook) ||
-	    !(d->disk = alloc_disk(1)) ||
-	    !(q = blk_alloc_queue(GFP_KERNEL)))
+	    !(d->disk = alloc_disk(1))) {
+		ida_simple_remove(&bcache_minor, minor);
 		return -ENOMEM;
+	}
 
 	set_capacity(d->disk, sectors);
-	snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
+	snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", minor);
 
 	d->disk->major		= bcache_major;
-	d->disk->first_minor	= bcache_minor++;
+	d->disk->first_minor	= minor;
 	d->disk->fops		= &bcache_ops;
 	d->disk->private_data	= d;
 
+	q = blk_alloc_queue(GFP_KERNEL);
+	if (!q)
+		return -ENOMEM;
+
 	blk_queue_make_request(q, NULL);
 	d->disk->queue			= q;
 	q->queuedata			= d;
@@ -874,7 +894,7 @@ static void cached_dev_detach_finish(struct work_struct *w)
 	struct closure cl;
 	closure_init_stack(&cl);
 
-	BUG_ON(!atomic_read(&dc->disk.detaching));
+	BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
 	BUG_ON(atomic_read(&dc->count));
 
 	mutex_lock(&bch_register_lock);
@@ -888,6 +908,8 @@ static void cached_dev_detach_finish(struct work_struct *w)
 	bcache_device_detach(&dc->disk);
 	list_move(&dc->list, &uncached_devices);
 
+	clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
+
 	mutex_unlock(&bch_register_lock);
 
 	pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
@@ -900,10 +922,10 @@ void bch_cached_dev_detach(struct cached_dev *dc)
 {
 	lockdep_assert_held(&bch_register_lock);
 
-	if (atomic_read(&dc->disk.closing))
+	if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
 		return;
 
-	if (atomic_xchg(&dc->disk.detaching, 1))
+	if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
 		return;
 
 	/*
@@ -1030,6 +1052,7 @@ static void cached_dev_free(struct closure *cl)
 	struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
 
 	cancel_delayed_work_sync(&dc->writeback_rate_update);
+	kthread_stop(dc->writeback_thread);
 
 	mutex_lock(&bch_register_lock);
 
@@ -1058,11 +1081,7 @@ static void cached_dev_flush(struct closure *cl)
 	struct bcache_device *d = &dc->disk;
 
 	mutex_lock(&bch_register_lock);
-	d->flush_done = 1;
-
-	if (d->c)
-		bcache_device_unlink(d);
-
+	bcache_device_unlink(d);
 	mutex_unlock(&bch_register_lock);
 
 	bch_cache_accounting_destroy(&dc->accounting);
@@ -1088,7 +1107,6 @@ static int cached_dev_init(struct cached_dev *dc, unsigned block_size)
 	spin_lock_init(&dc->io_lock);
 	bch_cache_accounting_init(&dc->accounting, &dc->disk.cl);
 
-	dc->sequential_merge		= true;
 	dc->sequential_cutoff		= 4 << 20;
 
 	for (io = dc->io; io < dc->io + RECENT_IO; io++) {
@@ -1260,7 +1278,8 @@ bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
 {
 	va_list args;
 
-	if (test_bit(CACHE_SET_STOPPING, &c->flags))
+	if (c->on_error != ON_ERROR_PANIC &&
+	    test_bit(CACHE_SET_STOPPING, &c->flags))
 		return false;
 
 	/* XXX: we can be called from atomic context
@@ -1275,6 +1294,9 @@ bool bch_cache_set_error(struct cache_set *c, const char *fmt, ...)
 
 	printk(", disabling caching\n");
 
+	if (c->on_error == ON_ERROR_PANIC)
+		panic("panic forced after error\n");
+
 	bch_cache_set_unregister(c);
 	return true;
 }
@@ -1339,6 +1361,9 @@ static void cache_set_flush(struct closure *cl)
 	kobject_put(&c->internal);
 	kobject_del(&c->kobj);
 
+	if (c->gc_thread)
+		kthread_stop(c->gc_thread);
+
 	if (!IS_ERR_OR_NULL(c->root))
 		list_add(&c->root->list, &c->btree_cache);
 
@@ -1433,12 +1458,19 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
 
 	c->sort_crit_factor = int_sqrt(c->btree_pages);
 
-	mutex_init(&c->bucket_lock);
-	mutex_init(&c->sort_lock);
-	spin_lock_init(&c->sort_time_lock);
 	closure_init_unlocked(&c->sb_write);
+	mutex_init(&c->bucket_lock);
+	init_waitqueue_head(&c->try_wait);
+	init_waitqueue_head(&c->bucket_wait);
 	closure_init_unlocked(&c->uuid_write);
-	spin_lock_init(&c->btree_read_time_lock);
+	mutex_init(&c->sort_lock);
+
+	spin_lock_init(&c->sort_time.lock);
+	spin_lock_init(&c->btree_gc_time.lock);
+	spin_lock_init(&c->btree_split_time.lock);
+	spin_lock_init(&c->btree_read_time.lock);
+	spin_lock_init(&c->try_harder_time.lock);
+
 	bch_moving_init_cache_set(c);
 
 	INIT_LIST_HEAD(&c->list);
@@ -1483,11 +1515,10 @@ static void run_cache_set(struct cache_set *c)
 	const char *err = "cannot allocate memory";
 	struct cached_dev *dc, *t;
 	struct cache *ca;
+	struct closure cl;
 	unsigned i;
 
-	struct btree_op op;
-	bch_btree_op_init_stack(&op);
-	op.lock = SHRT_MAX;
+	closure_init_stack(&cl);
 
 	for_each_cache(ca, c, i)
 		c->nbuckets += ca->sb.nbuckets;
@@ -1498,7 +1529,7 @@ static void run_cache_set(struct cache_set *c)
 		struct jset *j;
 
 		err = "cannot allocate memory for journal";
-		if (bch_journal_read(c, &journal, &op))
+		if (bch_journal_read(c, &journal))
 			goto err;
 
 		pr_debug("btree_journal_read() done");
@@ -1522,23 +1553,23 @@ static void run_cache_set(struct cache_set *c)
 		k = &j->btree_root;
 
 		err = "bad btree root";
-		if (__bch_ptr_invalid(c, j->btree_level + 1, k))
+		if (bch_btree_ptr_invalid(c, k))
 			goto err;
 
 		err = "error reading btree root";
-		c->root = bch_btree_node_get(c, k, j->btree_level, &op);
+		c->root = bch_btree_node_get(c, k, j->btree_level, true);
 		if (IS_ERR_OR_NULL(c->root))
 			goto err;
 
 		list_del_init(&c->root->list);
 		rw_unlock(true, c->root);
 
-		err = uuid_read(c, j, &op.cl);
+		err = uuid_read(c, j, &cl);
 		if (err)
 			goto err;
 
 		err = "error in recovery";
-		if (bch_btree_check(c, &op))
+		if (bch_btree_check(c))
 			goto err;
 
 		bch_journal_mark(c, &journal);
@@ -1570,11 +1601,9 @@ static void run_cache_set(struct cache_set *c)
 		if (j->version < BCACHE_JSET_VERSION_UUID)
 			__uuid_write(c);
 
-		bch_journal_replay(c, &journal, &op);
+		bch_journal_replay(c, &journal);
 	} else {
 		pr_notice("invalidating existing data");
-		/* Don't want invalidate_buckets() to queue a gc yet */
-		closure_lock(&c->gc, NULL);
 
 		for_each_cache(ca, c, i) {
 			unsigned j;
@@ -1600,15 +1629,15 @@ static void run_cache_set(struct cache_set *c)
 
 		err = "cannot allocate new UUID bucket";
 		if (__uuid_write(c))
-			goto err_unlock_gc;
+			goto err;
 
 		err = "cannot allocate new btree root";
-		c->root = bch_btree_node_alloc(c, 0, &op.cl);
+		c->root = bch_btree_node_alloc(c, 0, true);
 		if (IS_ERR_OR_NULL(c->root))
-			goto err_unlock_gc;
+			goto err;
 
 		bkey_copy_key(&c->root->key, &MAX_KEY);
-		bch_btree_node_write(c->root, &op.cl);
+		bch_btree_node_write(c->root, &cl);
 
 		bch_btree_set_root(c->root);
 		rw_unlock(true, c->root);
@@ -1621,14 +1650,14 @@ static void run_cache_set(struct cache_set *c)
 		SET_CACHE_SYNC(&c->sb, true);
 
 		bch_journal_next(&c->journal);
-		bch_journal_meta(c, &op.cl);
-
-		/* Unlock */
-		closure_set_stopped(&c->gc.cl);
-		closure_put(&c->gc.cl);
+		bch_journal_meta(c, &cl);
 	}
 
-	closure_sync(&op.cl);
+	err = "error starting gc thread";
+	if (bch_gc_thread_start(c))
+		goto err;
+
+	closure_sync(&cl);
 	c->sb.last_mount = get_seconds();
 	bcache_write_super(c);
 
@@ -1638,13 +1667,10 @@ static void run_cache_set(struct cache_set *c)
 	flash_devs_run(c);
 
 	return;
-err_unlock_gc:
-	closure_set_stopped(&c->gc.cl);
-	closure_put(&c->gc.cl);
 err:
-	closure_sync(&op.cl);
+	closure_sync(&cl);
 	/* XXX: test this, it's broken */
-	bch_cache_set_error(c, err);
+	bch_cache_set_error(c, "%s", err);
 }
 
 static bool can_attach_cache(struct cache *ca, struct cache_set *c)
@@ -1725,8 +1751,6 @@ void bch_cache_release(struct kobject *kobj)
 	if (ca->set)
 		ca->set->cache[ca->sb.nr_this_dev] = NULL;
 
-	bch_cache_allocator_exit(ca);
-
 	bio_split_pool_free(&ca->bio_split_hook);
 
 	free_pages((unsigned long) ca->disk_buckets, ilog2(bucket_pages(ca)));
@@ -1758,8 +1782,6 @@ static int cache_alloc(struct cache_sb *sb, struct cache *ca)
 	__module_get(THIS_MODULE);
 	kobject_init(&ca->kobj, &bch_cache_ktype);
 
-	INIT_LIST_HEAD(&ca->discards);
-
 	bio_init(&ca->journal.bio);
 	ca->journal.bio.bi_max_vecs = 8;
 	ca->journal.bio.bi_io_vec = ca->journal.bio.bi_inline_vecs;
@@ -2006,7 +2028,6 @@ static struct notifier_block reboot = {
 static void bcache_exit(void)
 {
 	bch_debug_exit();
-	bch_writeback_exit();
 	bch_request_exit();
 	bch_btree_exit();
 	if (bcache_kobj)
@@ -2039,7 +2060,6 @@ static int __init bcache_init(void)
 	    sysfs_create_files(bcache_kobj, files) ||
 	    bch_btree_init() ||
 	    bch_request_init() ||
-	    bch_writeback_init() ||
 	    bch_debug_init(bcache_kobj))
 		goto err;
 
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 924dcfdae111..80d4c2bee18a 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -21,6 +21,12 @@ static const char * const cache_replacement_policies[] = {
 	NULL
 };
 
+static const char * const error_actions[] = {
+	"unregister",
+	"panic",
+	NULL
+};
+
 write_attribute(attach);
 write_attribute(detach);
 write_attribute(unregister);
@@ -66,7 +72,6 @@ rw_attribute(congested_read_threshold_us);
 rw_attribute(congested_write_threshold_us);
 
 rw_attribute(sequential_cutoff);
-rw_attribute(sequential_merge);
 rw_attribute(data_csum);
 rw_attribute(cache_mode);
 rw_attribute(writeback_metadata);
@@ -90,11 +95,14 @@ rw_attribute(discard);
 rw_attribute(running);
 rw_attribute(label);
 rw_attribute(readahead);
+rw_attribute(errors);
 rw_attribute(io_error_limit);
 rw_attribute(io_error_halflife);
 rw_attribute(verify);
+rw_attribute(bypass_torture_test);
 rw_attribute(key_merging_disabled);
 rw_attribute(gc_always_rewrite);
+rw_attribute(expensive_debug_checks);
 rw_attribute(freelist_percent);
 rw_attribute(cache_replacement_policy);
 rw_attribute(btree_shrinker_disabled);
@@ -116,6 +124,7 @@ SHOW(__bch_cached_dev)
 
 	sysfs_printf(data_csum,		"%i", dc->disk.data_csum);
 	var_printf(verify,		"%i");
+	var_printf(bypass_torture_test,	"%i");
 	var_printf(writeback_metadata,	"%i");
 	var_printf(writeback_running,	"%i");
 	var_print(writeback_delay);
@@ -150,10 +159,9 @@ SHOW(__bch_cached_dev)
 	sysfs_hprint(dirty_data,
 		     bcache_dev_sectors_dirty(&dc->disk) << 9);
 
-	sysfs_hprint(stripe_size,	(1 << dc->disk.stripe_size_bits) << 9);
+	sysfs_hprint(stripe_size,	dc->disk.stripe_size << 9);
 	var_printf(partial_stripes_expensive,	"%u");
 
-	var_printf(sequential_merge,	"%i");
 	var_hprint(sequential_cutoff);
 	var_hprint(readahead);
 
@@ -185,6 +193,7 @@ STORE(__cached_dev)
 
 	sysfs_strtoul(data_csum,	dc->disk.data_csum);
 	d_strtoul(verify);
+	d_strtoul(bypass_torture_test);
 	d_strtoul(writeback_metadata);
 	d_strtoul(writeback_running);
 	d_strtoul(writeback_delay);
@@ -199,7 +208,6 @@ STORE(__cached_dev)
 			    dc->writeback_rate_p_term_inverse, 1, INT_MAX);
 	d_strtoul(writeback_rate_d_smooth);
 
-	d_strtoul(sequential_merge);
 	d_strtoi_h(sequential_cutoff);
 	d_strtoi_h(readahead);
 
@@ -311,7 +319,6 @@ static struct attribute *bch_cached_dev_files[] = {
 	&sysfs_stripe_size,
 	&sysfs_partial_stripes_expensive,
 	&sysfs_sequential_cutoff,
-	&sysfs_sequential_merge,
 	&sysfs_clear_stats,
 	&sysfs_running,
 	&sysfs_state,
@@ -319,6 +326,7 @@ static struct attribute *bch_cached_dev_files[] = {
 	&sysfs_readahead,
 #ifdef CONFIG_BCACHE_DEBUG
 	&sysfs_verify,
+	&sysfs_bypass_torture_test,
 #endif
 	NULL
 };
@@ -366,7 +374,7 @@ STORE(__bch_flash_dev)
 	}
 
 	if (attr == &sysfs_unregister) {
-		atomic_set(&d->detaching, 1);
+		set_bit(BCACHE_DEV_DETACHING, &d->flags);
 		bcache_device_stop(d);
 	}
 
@@ -481,7 +489,6 @@ lock_root:
 
 	sysfs_print(btree_used_percent,	btree_used(c));
 	sysfs_print(btree_nodes,	c->gc_stats.nodes);
-	sysfs_hprint(dirty_data,	c->gc_stats.dirty);
 	sysfs_hprint(average_key_size,	average_key_size(c));
 
 	sysfs_print(cache_read_races,
@@ -492,6 +499,10 @@ lock_root:
 	sysfs_print(writeback_keys_failed,
 		    atomic_long_read(&c->writeback_keys_failed));
 
+	if (attr == &sysfs_errors)
+		return bch_snprint_string_list(buf, PAGE_SIZE, error_actions,
+					       c->on_error);
+
 	/* See count_io_errors for why 88 */
 	sysfs_print(io_error_halflife,	c->error_decay * 88);
 	sysfs_print(io_error_limit,	c->error_limit >> IO_ERROR_SHIFT);
@@ -506,6 +517,8 @@ lock_root:
 	sysfs_print(active_journal_entries,	fifo_used(&c->journal.pin));
 	sysfs_printf(verify,			"%i", c->verify);
 	sysfs_printf(key_merging_disabled,	"%i", c->key_merging_disabled);
+	sysfs_printf(expensive_debug_checks,
+		     "%i", c->expensive_debug_checks);
 	sysfs_printf(gc_always_rewrite,		"%i", c->gc_always_rewrite);
 	sysfs_printf(btree_shrinker_disabled,	"%i", c->shrinker_disabled);
 	sysfs_printf(copy_gc_enabled,		"%i", c->copy_gc_enabled);
@@ -555,7 +568,7 @@ STORE(__bch_cache_set)
 	}
 
 	if (attr == &sysfs_trigger_gc)
-		bch_queue_gc(c);
+		wake_up_gc(c);
 
 	if (attr == &sysfs_prune_cache) {
 		struct shrink_control sc;
@@ -569,6 +582,15 @@ STORE(__bch_cache_set)
 	sysfs_strtoul(congested_write_threshold_us,
 		      c->congested_write_threshold_us);
 
+	if (attr == &sysfs_errors) {
+		ssize_t v = bch_read_string_list(buf, error_actions);
+
+		if (v < 0)
+			return v;
+
+		c->on_error = v;
+	}
+
 	if (attr == &sysfs_io_error_limit)
 		c->error_limit = strtoul_or_return(buf) << IO_ERROR_SHIFT;
 
@@ -579,6 +601,7 @@ STORE(__bch_cache_set)
 	sysfs_strtoul(journal_delay_ms,		c->journal_delay_ms);
 	sysfs_strtoul(verify,			c->verify);
 	sysfs_strtoul(key_merging_disabled,	c->key_merging_disabled);
+	sysfs_strtoul(expensive_debug_checks,	c->expensive_debug_checks);
 	sysfs_strtoul(gc_always_rewrite,	c->gc_always_rewrite);
 	sysfs_strtoul(btree_shrinker_disabled,	c->shrinker_disabled);
 	sysfs_strtoul(copy_gc_enabled,		c->copy_gc_enabled);
@@ -618,8 +641,8 @@ static struct attribute *bch_cache_set_files[] = {
 	&sysfs_cache_available_percent,
 
 	&sysfs_average_key_size,
-	&sysfs_dirty_data,
 
+	&sysfs_errors,
 	&sysfs_io_error_limit,
 	&sysfs_io_error_halflife,
 	&sysfs_congested,
@@ -653,6 +676,7 @@ static struct attribute *bch_cache_set_internal_files[] = {
 #ifdef CONFIG_BCACHE_DEBUG
 	&sysfs_verify,
 	&sysfs_key_merging_disabled,
+	&sysfs_expensive_debug_checks,
 #endif
 	&sysfs_gc_always_rewrite,
 	&sysfs_btree_shrinker_disabled,
diff --git a/drivers/md/bcache/trace.c b/drivers/md/bcache/trace.c
index f7b6c197f90f..adbc3df17a80 100644
--- a/drivers/md/bcache/trace.c
+++ b/drivers/md/bcache/trace.c
@@ -1,6 +1,5 @@
 #include "bcache.h"
 #include "btree.h"
-#include "request.h"
 
 #include <linux/blktrace_api.h>
 #include <linux/module.h>
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index 420dad545c7d..462214eeacbe 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -168,10 +168,14 @@ int bch_parse_uuid(const char *s, char *uuid)
 
 void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
 {
-	uint64_t now		= local_clock();
-	uint64_t duration	= time_after64(now, start_time)
+	uint64_t now, duration, last;
+
+	spin_lock(&stats->lock);
+
+	now		= local_clock();
+	duration	= time_after64(now, start_time)
 		? now - start_time : 0;
-	uint64_t last		= time_after64(now, stats->last)
+	last		= time_after64(now, stats->last)
 		? now - stats->last : 0;
 
 	stats->max_duration = max(stats->max_duration, duration);
@@ -188,6 +192,8 @@ void bch_time_stats_update(struct time_stats *stats, uint64_t start_time)
 	}
 
 	stats->last = now ?: 1;
+
+	spin_unlock(&stats->lock);
 }
 
 /**
diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
index ea345c6896f4..362c4b3f8b4a 100644
--- a/drivers/md/bcache/util.h
+++ b/drivers/md/bcache/util.h
@@ -15,28 +15,18 @@
 
 struct closure;
 
-#ifdef CONFIG_BCACHE_EDEBUG
+#ifdef CONFIG_BCACHE_DEBUG
 
 #define atomic_dec_bug(v)	BUG_ON(atomic_dec_return(v) < 0)
 #define atomic_inc_bug(v, i)	BUG_ON(atomic_inc_return(v) <= i)
 
-#else /* EDEBUG */
+#else /* DEBUG */
 
 #define atomic_dec_bug(v)	atomic_dec(v)
 #define atomic_inc_bug(v, i)	atomic_inc(v)
 
 #endif
 
-#define BITMASK(name, type, field, offset, size)		\
-static inline uint64_t name(const type *k)			\
-{ return (k->field >> offset) & ~(((uint64_t) ~0) << size); }	\
-								\
-static inline void SET_##name(type *k, uint64_t v)		\
-{								\
-	k->field &= ~(~((uint64_t) ~0 << size) << offset);	\
-	k->field |= v << offset;				\
-}
-
 #define DECLARE_HEAP(type, name)					\
 	struct {							\
 		size_t size, used;					\
@@ -388,6 +378,7 @@ ssize_t bch_snprint_string_list(char *buf, size_t size, const char * const list[
 ssize_t bch_read_string_list(const char *buf, const char * const list[]);
 
 struct time_stats {
+	spinlock_t	lock;
 	/*
 	 * all fields are in nanoseconds, averages are ewmas stored left shifted
 	 * by 8
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index ba3ee48320f2..99053b1251be 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -11,18 +11,11 @@
 #include "debug.h"
 #include "writeback.h"
 
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
 #include <trace/events/bcache.h>
 
-static struct workqueue_struct *dirty_wq;
-
-static void read_dirty(struct closure *);
-
-struct dirty_io {
-	struct closure		cl;
-	struct cached_dev	*dc;
-	struct bio		bio;
-};
-
 /* Rate limiting */
 
 static void __update_writeback_rate(struct cached_dev *dc)
@@ -72,9 +65,6 @@ out:
 	dc->writeback_rate_derivative = derivative;
 	dc->writeback_rate_change = change;
 	dc->writeback_rate_target = target;
-
-	schedule_delayed_work(&dc->writeback_rate_update,
-			      dc->writeback_rate_update_seconds * HZ);
 }
 
 static void update_writeback_rate(struct work_struct *work)
@@ -90,13 +80,16 @@ static void update_writeback_rate(struct work_struct *work)
 		__update_writeback_rate(dc);
 
 	up_read(&dc->writeback_lock);
+
+	schedule_delayed_work(&dc->writeback_rate_update,
+			      dc->writeback_rate_update_seconds * HZ);
 }
 
 static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
 {
 	uint64_t ret;
 
-	if (atomic_read(&dc->disk.detaching) ||
+	if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
 	    !dc->writeback_percent)
 		return 0;
 
@@ -105,37 +98,11 @@ static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
 	return min_t(uint64_t, ret, HZ);
 }
 
-/* Background writeback */
-
-static bool dirty_pred(struct keybuf *buf, struct bkey *k)
-{
-	return KEY_DIRTY(k);
-}
-
-static bool dirty_full_stripe_pred(struct keybuf *buf, struct bkey *k)
-{
-	uint64_t stripe;
-	unsigned nr_sectors = KEY_SIZE(k);
-	struct cached_dev *dc = container_of(buf, struct cached_dev,
-					     writeback_keys);
-	unsigned stripe_size = 1 << dc->disk.stripe_size_bits;
-
-	if (!KEY_DIRTY(k))
-		return false;
-
-	stripe = KEY_START(k) >> dc->disk.stripe_size_bits;
-	while (1) {
-		if (atomic_read(dc->disk.stripe_sectors_dirty + stripe) !=
-		    stripe_size)
-			return false;
-
-		if (nr_sectors <= stripe_size)
-			return true;
-
-		nr_sectors -= stripe_size;
-		stripe++;
-	}
-}
+struct dirty_io {
+	struct closure		cl;
+	struct cached_dev	*dc;
+	struct bio		bio;
+};
 
 static void dirty_init(struct keybuf_key *w)
 {
@@ -153,131 +120,6 @@ static void dirty_init(struct keybuf_key *w)
 	bch_bio_map(bio, NULL);
 }
 
-static void refill_dirty(struct closure *cl)
-{
-	struct cached_dev *dc = container_of(cl, struct cached_dev,
-					     writeback.cl);
-	struct keybuf *buf = &dc->writeback_keys;
-	bool searched_from_start = false;
-	struct bkey end = MAX_KEY;
-	SET_KEY_INODE(&end, dc->disk.id);
-
-	if (!atomic_read(&dc->disk.detaching) &&
-	    !dc->writeback_running)
-		closure_return(cl);
-
-	down_write(&dc->writeback_lock);
-
-	if (!atomic_read(&dc->has_dirty)) {
-		SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
-		bch_write_bdev_super(dc, NULL);
-
-		up_write(&dc->writeback_lock);
-		closure_return(cl);
-	}
-
-	if (bkey_cmp(&buf->last_scanned, &end) >= 0) {
-		buf->last_scanned = KEY(dc->disk.id, 0, 0);
-		searched_from_start = true;
-	}
-
-	if (dc->partial_stripes_expensive) {
-		uint64_t i;
-
-		for (i = 0; i < dc->disk.nr_stripes; i++)
-			if (atomic_read(dc->disk.stripe_sectors_dirty + i) ==
-			    1 << dc->disk.stripe_size_bits)
-				goto full_stripes;
-
-		goto normal_refill;
-full_stripes:
-		bch_refill_keybuf(dc->disk.c, buf, &end,
-				  dirty_full_stripe_pred);
-	} else {
-normal_refill:
-		bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
-	}
-
-	if (bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start) {
-		/* Searched the entire btree  - delay awhile */
-
-		if (RB_EMPTY_ROOT(&buf->keys)) {
-			atomic_set(&dc->has_dirty, 0);
-			cached_dev_put(dc);
-		}
-
-		if (!atomic_read(&dc->disk.detaching))
-			closure_delay(&dc->writeback, dc->writeback_delay * HZ);
-	}
-
-	up_write(&dc->writeback_lock);
-
-	bch_ratelimit_reset(&dc->writeback_rate);
-
-	/* Punt to workqueue only so we don't recurse and blow the stack */
-	continue_at(cl, read_dirty, dirty_wq);
-}
-
-void bch_writeback_queue(struct cached_dev *dc)
-{
-	if (closure_trylock(&dc->writeback.cl, &dc->disk.cl)) {
-		if (!atomic_read(&dc->disk.detaching))
-			closure_delay(&dc->writeback, dc->writeback_delay * HZ);
-
-		continue_at(&dc->writeback.cl, refill_dirty, dirty_wq);
-	}
-}
-
-void bch_writeback_add(struct cached_dev *dc)
-{
-	if (!atomic_read(&dc->has_dirty) &&
-	    !atomic_xchg(&dc->has_dirty, 1)) {
-		atomic_inc(&dc->count);
-
-		if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
-			SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
-			/* XXX: should do this synchronously */
-			bch_write_bdev_super(dc, NULL);
-		}
-
-		bch_writeback_queue(dc);
-
-		if (dc->writeback_percent)
-			schedule_delayed_work(&dc->writeback_rate_update,
-				      dc->writeback_rate_update_seconds * HZ);
-	}
-}
-
-void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
-				  uint64_t offset, int nr_sectors)
-{
-	struct bcache_device *d = c->devices[inode];
-	unsigned stripe_size, stripe_offset;
-	uint64_t stripe;
-
-	if (!d)
-		return;
-
-	stripe_size = 1 << d->stripe_size_bits;
-	stripe = offset >> d->stripe_size_bits;
-	stripe_offset = offset & (stripe_size - 1);
-
-	while (nr_sectors) {
-		int s = min_t(unsigned, abs(nr_sectors),
-			      stripe_size - stripe_offset);
-
-		if (nr_sectors < 0)
-			s = -s;
-
-		atomic_add(s, d->stripe_sectors_dirty + stripe);
-		nr_sectors -= s;
-		stripe_offset = 0;
-		stripe++;
-	}
-}
-
-/* Background writeback - IO loop */
-
 static void dirty_io_destructor(struct closure *cl)
 {
 	struct dirty_io *io = container_of(cl, struct dirty_io, cl);
@@ -297,26 +139,25 @@ static void write_dirty_finish(struct closure *cl)
 
 	/* This is kind of a dumb way of signalling errors. */
 	if (KEY_DIRTY(&w->key)) {
+		int ret;
 		unsigned i;
-		struct btree_op op;
-		bch_btree_op_init_stack(&op);
+		struct keylist keys;
 
-		op.type = BTREE_REPLACE;
-		bkey_copy(&op.replace, &w->key);
+		bch_keylist_init(&keys);
 
-		SET_KEY_DIRTY(&w->key, false);
-		bch_keylist_add(&op.keys, &w->key);
+		bkey_copy(keys.top, &w->key);
+		SET_KEY_DIRTY(keys.top, false);
+		bch_keylist_push(&keys);
 
 		for (i = 0; i < KEY_PTRS(&w->key); i++)
 			atomic_inc(&PTR_BUCKET(dc->disk.c, &w->key, i)->pin);
 
-		bch_btree_insert(&op, dc->disk.c);
-		closure_sync(&op.cl);
+		ret = bch_btree_insert(dc->disk.c, &keys, NULL, &w->key);
 
-		if (op.insert_collision)
+		if (ret)
 			trace_bcache_writeback_collision(&w->key);
 
-		atomic_long_inc(op.insert_collision
+		atomic_long_inc(ret
 				? &dc->disk.c->writeback_keys_failed
 				: &dc->disk.c->writeback_keys_done);
 	}
@@ -374,30 +215,33 @@ static void read_dirty_submit(struct closure *cl)
 	continue_at(cl, write_dirty, system_wq);
 }
 
-static void read_dirty(struct closure *cl)
+static void read_dirty(struct cached_dev *dc)
 {
-	struct cached_dev *dc = container_of(cl, struct cached_dev,
-					     writeback.cl);
-	unsigned delay = writeback_delay(dc, 0);
+	unsigned delay = 0;
 	struct keybuf_key *w;
 	struct dirty_io *io;
+	struct closure cl;
+
+	closure_init_stack(&cl);
 
 	/*
 	 * XXX: if we error, background writeback just spins. Should use some
 	 * mempools.
 	 */
 
-	while (1) {
+	while (!kthread_should_stop()) {
+		try_to_freeze();
+
 		w = bch_keybuf_next(&dc->writeback_keys);
 		if (!w)
 			break;
 
 		BUG_ON(ptr_stale(dc->disk.c, &w->key, 0));
 
-		if (delay > 0 &&
-		    (KEY_START(&w->key) != dc->last_read ||
-		     jiffies_to_msecs(delay) > 50))
-			delay = schedule_timeout_uninterruptible(delay);
+		if (KEY_START(&w->key) != dc->last_read ||
+		    jiffies_to_msecs(delay) > 50)
+			while (!kthread_should_stop() && delay)
+				delay = schedule_timeout_interruptible(delay);
 
 		dc->last_read	= KEY_OFFSET(&w->key);
 
@@ -423,7 +267,7 @@ static void read_dirty(struct closure *cl)
 		trace_bcache_writeback(&w->key);
 
 		down(&dc->in_flight);
-		closure_call(&io->cl, read_dirty_submit, NULL, cl);
+		closure_call(&io->cl, read_dirty_submit, NULL, &cl);
 
 		delay = writeback_delay(dc, KEY_SIZE(&w->key));
 	}
@@ -439,52 +283,205 @@ err:
 	 * Wait for outstanding writeback IOs to finish (and keybuf slots to be
 	 * freed) before refilling again
 	 */
-	continue_at(cl, refill_dirty, dirty_wq);
+	closure_sync(&cl);
 }
 
-/* Init */
+/* Scan for dirty data */
+
+void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
+				  uint64_t offset, int nr_sectors)
+{
+	struct bcache_device *d = c->devices[inode];
+	unsigned stripe_offset, stripe, sectors_dirty;
+
+	if (!d)
+		return;
+
+	stripe = offset_to_stripe(d, offset);
+	stripe_offset = offset & (d->stripe_size - 1);
+
+	while (nr_sectors) {
+		int s = min_t(unsigned, abs(nr_sectors),
+			      d->stripe_size - stripe_offset);
+
+		if (nr_sectors < 0)
+			s = -s;
+
+		if (stripe >= d->nr_stripes)
+			return;
+
+		sectors_dirty = atomic_add_return(s,
+					d->stripe_sectors_dirty + stripe);
+		if (sectors_dirty == d->stripe_size)
+			set_bit(stripe, d->full_dirty_stripes);
+		else
+			clear_bit(stripe, d->full_dirty_stripes);
+
+		nr_sectors -= s;
+		stripe_offset = 0;
+		stripe++;
+	}
+}
 
-static int bch_btree_sectors_dirty_init(struct btree *b, struct btree_op *op,
-					struct cached_dev *dc)
+static bool dirty_pred(struct keybuf *buf, struct bkey *k)
 {
-	struct bkey *k;
-	struct btree_iter iter;
-
-	bch_btree_iter_init(b, &iter, &KEY(dc->disk.id, 0, 0));
-	while ((k = bch_btree_iter_next_filter(&iter, b, bch_ptr_bad)))
-		if (!b->level) {
-			if (KEY_INODE(k) > dc->disk.id)
-				break;
-
-			if (KEY_DIRTY(k))
-				bcache_dev_sectors_dirty_add(b->c, dc->disk.id,
-							     KEY_START(k),
-							     KEY_SIZE(k));
-		} else {
-			btree(sectors_dirty_init, k, b, op, dc);
-			if (KEY_INODE(k) > dc->disk.id)
-				break;
-
-			cond_resched();
+	return KEY_DIRTY(k);
+}
+
+static void refill_full_stripes(struct cached_dev *dc)
+{
+	struct keybuf *buf = &dc->writeback_keys;
+	unsigned start_stripe, stripe, next_stripe;
+	bool wrapped = false;
+
+	stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned));
+
+	if (stripe >= dc->disk.nr_stripes)
+		stripe = 0;
+
+	start_stripe = stripe;
+
+	while (1) {
+		stripe = find_next_bit(dc->disk.full_dirty_stripes,
+				       dc->disk.nr_stripes, stripe);
+
+		if (stripe == dc->disk.nr_stripes)
+			goto next;
+
+		next_stripe = find_next_zero_bit(dc->disk.full_dirty_stripes,
+						 dc->disk.nr_stripes, stripe);
+
+		buf->last_scanned = KEY(dc->disk.id,
+					stripe * dc->disk.stripe_size, 0);
+
+		bch_refill_keybuf(dc->disk.c, buf,
+				  &KEY(dc->disk.id,
+				       next_stripe * dc->disk.stripe_size, 0),
+				  dirty_pred);
+
+		if (array_freelist_empty(&buf->freelist))
+			return;
+
+		stripe = next_stripe;
+next:
+		if (wrapped && stripe > start_stripe)
+			return;
+
+		if (stripe == dc->disk.nr_stripes) {
+			stripe = 0;
+			wrapped = true;
 		}
+	}
+}
+
+static bool refill_dirty(struct cached_dev *dc)
+{
+	struct keybuf *buf = &dc->writeback_keys;
+	struct bkey end = KEY(dc->disk.id, MAX_KEY_OFFSET, 0);
+	bool searched_from_start = false;
+
+	if (dc->partial_stripes_expensive) {
+		refill_full_stripes(dc);
+		if (array_freelist_empty(&buf->freelist))
+			return false;
+	}
+
+	if (bkey_cmp(&buf->last_scanned, &end) >= 0) {
+		buf->last_scanned = KEY(dc->disk.id, 0, 0);
+		searched_from_start = true;
+	}
+
+	bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
+
+	return bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start;
+}
+
+static int bch_writeback_thread(void *arg)
+{
+	struct cached_dev *dc = arg;
+	bool searched_full_index;
+
+	while (!kthread_should_stop()) {
+		down_write(&dc->writeback_lock);
+		if (!atomic_read(&dc->has_dirty) ||
+		    (!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) &&
+		     !dc->writeback_running)) {
+			up_write(&dc->writeback_lock);
+			set_current_state(TASK_INTERRUPTIBLE);
+
+			if (kthread_should_stop())
+				return 0;
+
+			try_to_freeze();
+			schedule();
+			continue;
+		}
+
+		searched_full_index = refill_dirty(dc);
+
+		if (searched_full_index &&
+		    RB_EMPTY_ROOT(&dc->writeback_keys.keys)) {
+			atomic_set(&dc->has_dirty, 0);
+			cached_dev_put(dc);
+			SET_BDEV_STATE(&dc->sb, BDEV_STATE_CLEAN);
+			bch_write_bdev_super(dc, NULL);
+		}
+
+		up_write(&dc->writeback_lock);
+
+		bch_ratelimit_reset(&dc->writeback_rate);
+		read_dirty(dc);
+
+		if (searched_full_index) {
+			unsigned delay = dc->writeback_delay * HZ;
+
+			while (delay &&
+			       !kthread_should_stop() &&
+			       !test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
+				delay = schedule_timeout_interruptible(delay);
+		}
+	}
 
 	return 0;
 }
 
+/* Init */
+
+struct sectors_dirty_init {
+	struct btree_op	op;
+	unsigned	inode;
+};
+
+static int sectors_dirty_init_fn(struct btree_op *_op, struct btree *b,
+				 struct bkey *k)
+{
+	struct sectors_dirty_init *op = container_of(_op,
+						struct sectors_dirty_init, op);
+	if (KEY_INODE(k) > op->inode)
+		return MAP_DONE;
+
+	if (KEY_DIRTY(k))
+		bcache_dev_sectors_dirty_add(b->c, KEY_INODE(k),
+					     KEY_START(k), KEY_SIZE(k));
+
+	return MAP_CONTINUE;
+}
+
 void bch_sectors_dirty_init(struct cached_dev *dc)
 {
-	struct btree_op op;
+	struct sectors_dirty_init op;
+
+	bch_btree_op_init(&op.op, -1);
+	op.inode = dc->disk.id;
 
-	bch_btree_op_init_stack(&op);
-	btree_root(sectors_dirty_init, dc->disk.c, &op, dc);
+	bch_btree_map_keys(&op.op, dc->disk.c, &KEY(op.inode, 0, 0),
+			   sectors_dirty_init_fn, 0);
 }
 
-void bch_cached_dev_writeback_init(struct cached_dev *dc)
+int bch_cached_dev_writeback_init(struct cached_dev *dc)
 {
 	sema_init(&dc->in_flight, 64);
-	closure_init_unlocked(&dc->writeback);
 	init_rwsem(&dc->writeback_lock);
-
 	bch_keybuf_init(&dc->writeback_keys);
 
 	dc->writeback_metadata		= true;
@@ -498,22 +495,16 @@ void bch_cached_dev_writeback_init(struct cached_dev *dc)
 	dc->writeback_rate_p_term_inverse = 64;
 	dc->writeback_rate_d_smooth	= 8;
 
+	dc->writeback_thread = kthread_create(bch_writeback_thread, dc,
+					      "bcache_writeback");
+	if (IS_ERR(dc->writeback_thread))
+		return PTR_ERR(dc->writeback_thread);
+
+	set_task_state(dc->writeback_thread, TASK_INTERRUPTIBLE);
+
 	INIT_DELAYED_WORK(&dc->writeback_rate_update, update_writeback_rate);
 	schedule_delayed_work(&dc->writeback_rate_update,
 			      dc->writeback_rate_update_seconds * HZ);
-}
-
-void bch_writeback_exit(void)
-{
-	if (dirty_wq)
-		destroy_workqueue(dirty_wq);
-}
-
-int __init bch_writeback_init(void)
-{
-	dirty_wq = create_workqueue("bcache_writeback");
-	if (!dirty_wq)
-		return -ENOMEM;
 
 	return 0;
 }
diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index c91f61bb95b6..c9ddcf4614b9 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -14,20 +14,27 @@ static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
 	return ret;
 }
 
-static inline bool bcache_dev_stripe_dirty(struct bcache_device *d,
+static inline unsigned offset_to_stripe(struct bcache_device *d,
+					uint64_t offset)
+{
+	do_div(offset, d->stripe_size);
+	return offset;
+}
+
+static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
 					   uint64_t offset,
 					   unsigned nr_sectors)
 {
-	uint64_t stripe = offset >> d->stripe_size_bits;
+	unsigned stripe = offset_to_stripe(&dc->disk, offset);
 
 	while (1) {
-		if (atomic_read(d->stripe_sectors_dirty + stripe))
+		if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
 			return true;
 
-		if (nr_sectors <= 1 << d->stripe_size_bits)
+		if (nr_sectors <= dc->disk.stripe_size)
 			return false;
 
-		nr_sectors -= 1 << d->stripe_size_bits;
+		nr_sectors -= dc->disk.stripe_size;
 		stripe++;
 	}
 }
@@ -38,12 +45,12 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
 	unsigned in_use = dc->disk.c->gc_stats.in_use;
 
 	if (cache_mode != CACHE_MODE_WRITEBACK ||
-	    atomic_read(&dc->disk.detaching) ||
+	    test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
 	    in_use > CUTOFF_WRITEBACK_SYNC)
 		return false;
 
 	if (dc->partial_stripes_expensive &&
-	    bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
+	    bcache_dev_stripe_dirty(dc, bio->bi_sector,
 				    bio_sectors(bio)))
 		return true;
 
@@ -54,11 +61,30 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
 		in_use <= CUTOFF_WRITEBACK;
 }
 
+static inline void bch_writeback_queue(struct cached_dev *dc)
+{
+	wake_up_process(dc->writeback_thread);
+}
+
+static inline void bch_writeback_add(struct cached_dev *dc)
+{
+	if (!atomic_read(&dc->has_dirty) &&
+	    !atomic_xchg(&dc->has_dirty, 1)) {
+		atomic_inc(&dc->count);
+
+		if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
+			SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
+			/* XXX: should do this synchronously */
+			bch_write_bdev_super(dc, NULL);
+		}
+
+		bch_writeback_queue(dc);
+	}
+}
+
 void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
-void bch_writeback_queue(struct cached_dev *);
-void bch_writeback_add(struct cached_dev *);
 
 void bch_sectors_dirty_init(struct cached_dev *dc);
-void bch_cached_dev_writeback_init(struct cached_dev *);
+int bch_cached_dev_writeback_init(struct cached_dev *);
 
 #endif