Index: linux-2.6/drivers/md/persistent-data/dm-block-manager.c
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-block-manager.c
+++ linux-2.6/drivers/md/persistent-data/dm-block-manager.c
@@ -601,6 +601,38 @@ void dm_bm_unlock(struct dm_block *b)
 }
 EXPORT_SYMBOL_GPL(dm_bm_unlock);
 
+void dm_bm_fast_lock(struct dm_block_manager *bm)
+{
+	dm_bufio_lock_read(bm->bufio);
+}
+
+void dm_bm_fast_unlock(struct dm_block_manager *bm)
+{
+	dm_bufio_unlock_read(bm->bufio);
+}
+
+int dm_bm_fast_get_block(struct dm_block_manager *bm,
+			 dm_block_t b, struct dm_block_validator *v,
+			 struct dm_block **result)
+{
+	int r;
+	struct buffer_aux *aux;
+	void *p;
+
+	p = dm_bufio_get_unlocked(bm->bufio, b, (struct dm_buffer **) result);
+	if (IS_ERR(p))
+		return PTR_ERR(p);
+	if (unlikely(!p))
+		return -EWOULDBLOCK;
+
+	aux = dm_bufio_get_aux_data(to_buffer(*result));
+	r = dm_bm_validate_buffer(bm, to_buffer(*result), aux, v);
+	if (unlikely(r))
+		return r;
+
+	return 0;
+}
+
 int dm_bm_flush(struct dm_block_manager *bm)
 {
 	if (dm_bm_is_read_only(bm))
Index: linux-2.6/drivers/md/persistent-data/dm-block-manager.h
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-block-manager.h
+++ linux-2.6/drivers/md/persistent-data/dm-block-manager.h
@@ -96,6 +96,12 @@ int dm_bm_write_lock_zero(struct dm_bloc
 
 void dm_bm_unlock(struct dm_block *b);
 
+void dm_bm_fast_lock(struct dm_block_manager *bm);
+void dm_bm_fast_unlock(struct dm_block_manager *bm);
+int dm_bm_fast_get_block(struct dm_block_manager *bm,
+			 dm_block_t b, struct dm_block_validator *v,
+			 struct dm_block **result);
+
 /*
  * It's a common idiom to have a superblock that should be committed last.
  *
Index: linux-2.6/drivers/md/persistent-data/dm-btree-internal.h
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-btree-internal.h
+++ linux-2.6/drivers/md/persistent-data/dm-btree-internal.h
@@ -64,9 +64,11 @@ struct ro_spine {
 	struct dm_btree_info *info;
 
 	struct dm_block *node;
+	bool fast_locked;
+	bool fast_lock_failed;
 };
 
-void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
+void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info, bool disable_fast_access);
 void exit_ro_spine(struct ro_spine *s);
 int ro_step(struct ro_spine *s, dm_block_t new_child);
 struct btree_node *ro_node(struct ro_spine *s);
Index: linux-2.6/drivers/md/persistent-data/dm-btree-spine.c
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-btree-spine.c
+++ linux-2.6/drivers/md/persistent-data/dm-btree-spine.c
@@ -118,27 +118,60 @@ void unlock_block(struct dm_btree_info *
 	dm_tm_unlock(info->tm, b);
 }
 
+static void bn_fast_lock(struct dm_btree_info *info)
+{
+	dm_tm_fast_lock(info->tm);
+}
+
+static void bn_fast_unlock(struct dm_btree_info *info)
+{
+	dm_tm_fast_unlock(info->tm);
+}
+
+static int bn_fast_get_block(struct dm_btree_info *info, dm_block_t b,
+		      struct dm_block **result)
+{
+	return dm_tm_fast_get_block(info->tm, b, &btree_node_validator, result);
+}
+
 /*----------------------------------------------------------------*/
 
-void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
+void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info, bool disable_fast_access)
 {
 	s->info = info;
 	s->node = NULL;
+	s->fast_locked = false;
+	s->fast_lock_failed = disable_fast_access;
 }
 
 void exit_ro_spine(struct ro_spine *s)
 {
-	if (s->node)
+	if (s->fast_locked)
+		bn_fast_unlock(s->info);
+	else if (s->node)
 		unlock_block(s->info, s->node);
 }
 
 int ro_step(struct ro_spine *s, dm_block_t new_child)
 {
 	if (s->node) {
-		unlock_block(s->info, s->node);
+		if (unlikely(!s->fast_locked))
+			unlock_block(s->info, s->node);
 		s->node = NULL;
 	}
-
+	if (likely(!s->fast_lock_failed)) {
+		int r;
+		if (!s->fast_locked) {
+			bn_fast_lock(s->info);
+			s->fast_locked = true;
+		}
+		r = bn_fast_get_block(s->info, new_child, &s->node);
+		if (likely(!r))
+			return 0;
+		s->fast_lock_failed = true;
+		s->fast_locked = false;
+		bn_fast_unlock(s->info);
+	}
 	return bn_read_lock(s->info, new_child, &s->node);
 }
 
Index: linux-2.6/drivers/md/persistent-data/dm-transaction-manager.c
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-transaction-manager.c
+++ linux-2.6/drivers/md/persistent-data/dm-transaction-manager.c
@@ -348,6 +348,23 @@ void dm_tm_unlock(struct dm_transaction_
 }
 EXPORT_SYMBOL_GPL(dm_tm_unlock);
 
+void dm_tm_fast_lock(struct dm_transaction_manager *tm)
+{
+	dm_bm_fast_lock(tm->is_clone ? tm->real->bm : tm->bm);
+}
+
+void dm_tm_fast_unlock(struct dm_transaction_manager *tm)
+{
+	dm_bm_fast_unlock(tm->is_clone ? tm->real->bm : tm->bm);
+}
+
+int dm_tm_fast_get_block(struct dm_transaction_manager *tm, dm_block_t b,
+			 struct dm_block_validator *v,
+			 struct dm_block **blk)
+{
+	return dm_bm_fast_get_block(tm->is_clone ? tm->real->bm : tm->bm, b, v, blk);
+}
+
 void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
 {
 	/*
Index: linux-2.6/drivers/md/persistent-data/dm-transaction-manager.h
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-transaction-manager.h
+++ linux-2.6/drivers/md/persistent-data/dm-transaction-manager.h
@@ -96,6 +96,12 @@ int dm_tm_read_lock(struct dm_transactio
 
 void dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b);
 
+void dm_tm_fast_lock(struct dm_transaction_manager *tm);
+void dm_tm_fast_unlock(struct dm_transaction_manager *tm);
+int dm_tm_fast_get_block(struct dm_transaction_manager *tm, dm_block_t b,
+			 struct dm_block_validator *v,
+			 struct dm_block **blk);
+
 /*
  * Functions for altering the reference count of a block directly.
  */
Index: linux-2.6/drivers/md/persistent-data/dm-btree.c
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-btree.c
+++ linux-2.6/drivers/md/persistent-data/dm-btree.c
@@ -377,7 +377,7 @@ int dm_btree_lookup(struct dm_btree_info
 	__le64 internal_value_le;
 	struct ro_spine spine;
 
-	init_ro_spine(&spine, info);
+	init_ro_spine(&spine, info, false);
 	for (level = 0; level < info->levels; level++) {
 		size_t size;
 		void *value_p;
@@ -472,7 +472,7 @@ int dm_btree_lookup_next(struct dm_btree
 	__le64 internal_value_le;
 	struct ro_spine spine;
 
-	init_ro_spine(&spine, info);
+	init_ro_spine(&spine, info, true);
 	for (level = 0; level < info->levels - 1u; level++) {
 		r = btree_lookup_raw(&spine, root, keys[level],
 				     lower_bound, rkey,
@@ -1369,7 +1369,7 @@ static int dm_btree_find_key(struct dm_b
 	int r = 0, count = 0, level;
 	struct ro_spine spine;
 
-	init_ro_spine(&spine, info);
+	init_ro_spine(&spine, info, false);
 	for (level = 0; level < info->levels; level++) {
 		r = find_key(&spine, root, find_highest, result_keys + level,
 			     level == info->levels - 1 ? NULL : &root);
