diff --git a/configure.d/1_bio_gendisk.conf b/configure.d/1_bio_gendisk.conf
new file mode 100644
index 0000000..475b43e
--- /dev/null
+++ b/configure.d/1_bio_gendisk.conf
@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+	if compile_module $cur_name "struct bio *bio; bio->bi_disk;" "linux/blk_types.h"
+	then
+		echo $cur_name "1" >> $config_file_path
+	elif compile_module $cur_name "struct bio *bio; bio->bi_bdev;" "linux/blk_types.h"
+    then
+		echo $cur_name "2" >> $config_file_path
+	else
+		echo $cur_name "X" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+	    add_define "CAS_BIO_GET_GENDISK(bio) (bio->bi_disk)" ;;
+    "2")
+	    add_define "CAS_BIO_GET_GENDISK(bio) (bio->bi_bdev->bd_disk)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_flush_flag.conf b/configure.d/1_flush_flag.conf
index 0648fc9..5dd9d26 100644
--- a/configure.d/1_flush_flag.conf
+++ b/configure.d/1_flush_flag.conf
@@ -9,12 +9,15 @@
 check() {
 	cur_name=$(basename $2)
 	config_file_path=$1
-	if compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+    if compile_module $cur_name "BIO_FLUSH" "linux/bio.h"
 	then
 		echo $cur_name "1" >> $config_file_path
 	elif compile_module $cur_name "REQ_FLUSH" "linux/blk_types.h"
 	then
 		echo $cur_name "2" >> $config_file_path
+	elif compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "3" >> $config_file_path
     else
         echo $cur_name "X" >> $config_file_path
     fi
@@ -23,15 +26,26 @@ check() {
 apply() {
     case "$1" in
     "1")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_PREFLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & BIO_FLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | BIO_FLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~BIO_FLUSH)" ;;
     "2")
-		add_define "CAS_REQ_FLUSH \\
-			REQ_FLUSH"
-		add_define "CAS_FLUSH_SUPPORTED \\
-			1" ;;
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & REQ_FLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | REQ_FLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~REQ_FLUSH)" ;;
+    "3")
+        add_define "CAS_IS_SET_FLUSH(flags) \\
+            ((flags) & REQ_PREFLUSH)"
+        add_define "CAS_SET_FLUSH(flags) \\
+            ((flags) | REQ_PREFLUSH)"
+        add_define "CAS_CLEAR_FLUSH(flags) \\
+            ((flags) & ~REQ_PREFLUSH)" ;;
     *)
         exit 1
     esac
diff --git a/configure.d/1_make_request.conf b/configure.d/1_make_request.conf
index ded54f5..b1f3f6d 100644
--- a/configure.d/1_make_request.conf
+++ b/configure.d/1_make_request.conf
@@ -12,8 +12,11 @@ check() {
     if compile_module $cur_name "blk_queue_make_request" "linux/blkdev.h"
     then
         echo $cur_name "1" >> $config_file_path
-    else
+    elif compile_module $cur_name "struct request_queue *q; q->make_request_fn;" "linux/blkdev.h"
+    then
         echo $cur_name "2" >> $config_file_path
+    else
+        echo $cur_name "3" >> $config_file_path
     fi
 }
 
@@ -33,6 +36,13 @@ apply() {
         {
             q->make_request_fn = mfn;
         }" ;;
+    "3")
+		add_define "make_request_fn void"
+        add_function "
+        static inline void cas_blk_queue_make_request(struct request_queue *q,
+                make_request_fn *mfn)
+        {
+        }" ;;
     *)
         exit 1
     esac
diff --git a/configure.d/1_req_flush.conf b/configure.d/1_req_flush.conf
new file mode 100644
index 0000000..0648fc9
--- /dev/null
+++ b/configure.d/1_req_flush.conf
@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+	cur_name=$(basename $2)
+	config_file_path=$1
+	if compile_module $cur_name "REQ_PREFLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "1" >> $config_file_path
+	elif compile_module $cur_name "REQ_FLUSH" "linux/blk_types.h"
+	then
+		echo $cur_name "2" >> $config_file_path
+    else
+        echo $cur_name "X" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+		add_define "CAS_REQ_FLUSH \\
+			REQ_PREFLUSH"
+		add_define "CAS_FLUSH_SUPPORTED \\
+			1" ;;
+    "2")
+		add_define "CAS_REQ_FLUSH \\
+			REQ_FLUSH"
+		add_define "CAS_FLUSH_SUPPORTED \\
+			1" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/1_set_submit_bio.conf b/configure.d/1_set_submit_bio.conf
new file mode 100644
index 0000000..8938c54
--- /dev/null
+++ b/configure.d/1_set_submit_bio.conf
@@ -0,0 +1,31 @@
+#!/bin/bash
+#
+# Copyright(c) 2012-2021 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+. $(dirname $3)/conf_framework
+
+check() {
+    cur_name=$(basename $2)
+    config_file_path=$1
+    if compile_module $cur_name "struct block_device_operations *ops; ops->submit_bio;" "linux/blkdev.h"
+    then
+        echo $cur_name "1" >> $config_file_path
+    else
+        echo $cur_name "2" >> $config_file_path
+    fi
+}
+
+apply() {
+    case "$1" in
+    "1")
+		add_define "CAS_SET_SUBMIT_BIO(_fn) .submit_bio = _fn," ;;
+    "2")
+		add_define "CAS_SET_SUBMIT_BIO(_fn)" ;;
+    *)
+        exit 1
+    esac
+}
+
+conf_run $@
diff --git a/configure.d/2_queue_write.conf b/configure.d/2_queue_write.conf
index 98e620b..64908fd 100644
--- a/configure.d/2_queue_write.conf
+++ b/configure.d/2_queue_write.conf
@@ -35,7 +35,7 @@ apply() {
 	}" ;;
     "2")
 		add_define "CAS_CHECK_QUEUE_FLUSH(q) \\
-			((q)->flush_flags & CAS_REQ_FLUSH)"
+			CAS_IS_SET_FLUSH((q)->flush_flags)"
 		add_define "CAS_CHECK_QUEUE_FUA(q) \\
 			((q)->flush_flags & REQ_FUA)"
 		add_function "static inline void cas_set_queue_flush_fua(struct request_queue *q,
@@ -43,7 +43,7 @@ apply() {
 	{
 		unsigned int flags = 0;
 		if (flush)
-			flags |= CAS_REQ_FLUSH;
+			flags = CAS_SET_FLUSH(flags);
 		if (fua)
 			flags |= REQ_FUA;
 		if (flags)
diff --git a/modules/cas_cache/volume/obj_blk.h b/modules/cas_cache/volume/obj_blk.h
index a9af2f7..00d3a38 100644
--- a/modules/cas_cache/volume/obj_blk.h
+++ b/modules/cas_cache/volume/obj_blk.h
@@ -31,8 +31,11 @@ struct bd_object {
 	atomic64_t pending_rqs;
 		/*!< This fields describes in flight IO requests */
 
-	struct workqueue_struct *workqueue;
-		/*< Workqueue for internally trigerred I/O */
+	struct workqueue_struct *btm_wq;
+		/*< Workqueue for I/O internally trigerred in bottom vol */
+
+	struct workqueue_struct *expobj_wq;
+		/*< Workqueue for I/O handled by top vol */
 };
 
 static inline struct bd_object *bd_object(ocf_volume_t vol)
diff --git a/modules/cas_cache/volume/vol_atomic_dev_bottom.c b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
index 376ca91..82046a5 100644
--- a/modules/cas_cache/volume/vol_atomic_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_atomic_dev_bottom.c
@@ -903,8 +903,7 @@ void cas_atomic_submit_io(struct ocf_io *io)
 {
 	CAS_DEBUG_TRACE();
 
-	if (!CAS_IS_WRITE_FLUSH_FUA(io->flags) &&
-			CAS_IS_WRITE_FLUSH(io->flags)) {
+	if (CAS_IS_SET_FLUSH(io->flags)) {
 		/* FLUSH */
 		cas_atomic_submit_flush(io);
 		return;
@@ -953,8 +952,8 @@ void cas_atomic_close_object(ocf_volume_t volume)
 {
 	struct bd_object *bdobj = bd_object(volume);
 
-	if(bdobj->workqueue)
-		destroy_workqueue(bdobj->workqueue);
+	if(bdobj->btm_wq)
+		destroy_workqueue(bdobj->btm_wq);
 
 	block_dev_close_object(volume);
 }
@@ -976,8 +975,8 @@ int cas_atomic_open_object(ocf_volume_t volume, void *volume_params)
 	memcpy(&bdobj->atomic_params, volume_params,
 			sizeof(bdobj->atomic_params));
 
-	bdobj->workqueue = create_workqueue("CAS_AT_ZER");
-	if (!bdobj->workqueue) {
+	bdobj->btm_wq = create_workqueue("CAS_AT_ZER");
+	if (!bdobj->btm_wq) {
 		cas_atomic_close_object(volume);
 		result = -ENOMEM;
 		goto end;
@@ -1036,7 +1035,7 @@ static void _cas_atomic_write_zeroes_step_cmpl(struct ocf_io *io, int error)
 		_cas_atomic_write_zeroes_end(ctx, error);
 	} else {
 		/* submit next IO from work context */
-		queue_work(bdobj->workqueue, &ctx->cmpl_work);
+		queue_work(bdobj->btm_wq, &ctx->cmpl_work);
 	}
 }
 
diff --git a/modules/cas_cache/volume/vol_block_dev_bottom.c b/modules/cas_cache/volume/vol_block_dev_bottom.c
index 7109bda..dae8728 100644
--- a/modules/cas_cache/volume/vol_block_dev_bottom.c
+++ b/modules/cas_cache/volume/vol_block_dev_bottom.c
@@ -267,7 +267,7 @@ static void block_dev_submit_flush(struct ocf_io *io)
 	bio->bi_private = io;
 
 	atomic_inc(&blkio->rq_remaning);
-	cas_submit_bio(CAS_WRITE_FLUSH, bio);
+	cas_submit_bio(CAS_SET_FLUSH(0), bio);
 
 out:
 	cas_bd_io_end(io, blkio->error);
@@ -412,8 +412,7 @@ static void block_dev_submit_io(struct ocf_io *io)
 	uint32_t bytes = io->bytes;
 	int dir = io->dir;
 
-	if (!CAS_IS_WRITE_FLUSH_FUA(io->flags) &&
-			CAS_IS_WRITE_FLUSH(io->flags)) {
+	if (CAS_IS_SET_FLUSH(io->flags)) {
 		CAS_DEBUG_MSG("Flush request");
 		/* It is flush requests handle it */
 		block_dev_submit_flush(io);
diff --git a/modules/cas_cache/volume/vol_block_dev_top.c b/modules/cas_cache/volume/vol_block_dev_top.c
index 1820827..01af060 100644
--- a/modules/cas_cache/volume/vol_block_dev_top.c
+++ b/modules/cas_cache/volume/vol_block_dev_top.c
@@ -73,34 +73,13 @@ static inline void _blockdev_end_io_acct(struct bio *bio,
 	cas_generic_end_io_acct(gd->queue, bio, &gd->part0, start_time);
 }
 
-void block_dev_start_bio_fast(struct ocf_io *io)
+void block_dev_start_bio(struct ocf_io *io)
 {
 	struct blk_data *data = ocf_io_get_data(io);
 	struct bio *bio = data->master_io_req;
 
 	data->start_time = _blockdev_start_io_acct(bio);
 }
-
-void block_dev_complete_bio_fast(struct ocf_io *io, int error)
-{
-	struct blk_data *data = ocf_io_get_data(io);
-	struct bio *bio = data->master_io_req;
-
-	_blockdev_end_io_acct(bio, data->start_time);
-
-	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-}
-
-void block_dev_complete_bio_discard(struct ocf_io *io, int error)
-{
-	struct bio *bio = io->priv1;
-
-	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
-	ocf_io_put(io);
-}
-
 void block_dev_complete_rq(struct ocf_io *io, int error)
 
 {
@@ -507,23 +486,6 @@ static inline int _blkdev_can_hndl_bio(struct bio *bio)
 	return 0;
 }
 
-static inline bool _blkdev_is_flush_fua_bio(struct bio *bio)
-{
-	if (CAS_IS_WRITE_FLUSH_FUA(CAS_BIO_OP_FLAGS(bio))) {
-		/* FLUSH and FUA */
-		return true;
-	} else if (CAS_IS_WRITE_FUA(CAS_BIO_OP_FLAGS(bio))) {
-		/* FUA */
-		return true;
-	} else if (CAS_IS_WRITE_FLUSH(CAS_BIO_OP_FLAGS(bio))) {
-		/* FLUSH */
-		return true;
-
-	}
-
-	return false;
-}
-
 void _blockdev_set_exported_object_flush_fua(ocf_core_t core)
 {
 #ifdef CAS_FLUSH_SUPPORTED
@@ -670,10 +632,125 @@ static void _blockdev_pending_req_dec(struct casdsk_disk *dsk, void *private)
 	atomic64_dec(&bvol->pending_rqs);
 }
 
-static void _blockdev_make_request_discard(struct casdsk_disk *dsk,
-		struct request_queue *q, struct bio *bio, void *private)
+struct defer_bio_context {
+	struct work_struct io_work;
+	void (*cb)(ocf_core_t core, struct bio *bio);
+	ocf_core_t core;
+	struct bio *bio;
+};
+
+static void _blockdev_defer_bio_work(struct work_struct *work)
+{
+	struct defer_bio_context *context;
+
+	context = container_of(work, struct defer_bio_context, io_work);
+	context->cb(context->core, context->bio);
+	kfree(context);
+}
+
+static void _blockdev_defer_bio(ocf_core_t core, struct bio *bio,
+	void (*cb)(ocf_core_t core, struct bio *bio))
+{
+	struct defer_bio_context *context;
+	ocf_volume_t volume = ocf_core_get_volume(core);
+	struct bd_object *bvol = bd_object(volume);
+
+	BUG_ON(!bvol->expobj_wq);
+
+	context = kmalloc(sizeof(*context), GFP_ATOMIC);
+	if (!context) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+			CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	context->cb = cb;
+	context->bio = bio;
+	context->core = core;
+	INIT_WORK(&context->io_work, _blockdev_defer_bio_work);
+	queue_work(bvol->expobj_wq, &context->io_work);
+}
+
+static void block_dev_complete_data(struct ocf_io *io, int error)
+{
+	struct blk_data *data = ocf_io_get_data(io);
+	struct bio *bio = data->master_io_req;
+
+	_blockdev_end_io_acct(bio, data->start_time);
+
+	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
+	ocf_io_put(io);
+	cas_free_blk_data(data);
+}
+
+static void _blockdev_handle_data(ocf_core_t core, struct bio *bio)
+{
+	ocf_cache_t cache;
+	struct cache_priv *cache_priv;
+	struct ocf_io *io;
+	struct blk_data *data;
+	uint64_t flags = CAS_BIO_OP_FLAGS(bio);
+	int ret;
+
+	cache = ocf_core_get_cache(core);
+	cache_priv = ocf_cache_get_priv(cache);
+
+	if (unlikely(CAS_BIO_BISIZE(bio) == 0)) {
+		CAS_PRINT_RL(KERN_ERR
+			"Not able to handle empty BIO, flags = "
+			CAS_BIO_OP_FLAGS_FORMAT "\n",  CAS_BIO_OP_FLAGS(bio));
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
+		return;
+	}
+
+	data = cas_alloc_blk_data(bio_segments(bio), GFP_NOIO);
+	if (!data) {
+		CAS_PRINT_RL(KERN_CRIT "BIO data vector allocation error\n");
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	_blockdev_set_bio_data(data, bio);
+
+	data->master_io_req = bio;
+
+	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
+			CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
+			CAS_BIO_BISIZE(bio), (bio_data_dir(bio) == READ) ?
+					OCF_READ : OCF_WRITE,
+			cas_cls_classify(cache, bio), CAS_CLEAR_FLUSH(flags));
+
+	if (!io) {
+		printk(KERN_CRIT "Out of memory. Ending IO processing.\n");
+		cas_free_blk_data(data);
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
+		return;
+	}
+
+	ret = ocf_io_set_data(io, data, 0);
+	if (ret < 0) {
+		ocf_io_put(io);
+		cas_free_blk_data(data);
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
+		return;
+	}
+
+	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_data);
+	ocf_io_set_start(io, block_dev_start_bio);
+
+	ocf_core_submit_io(io);
+}
+
+static void block_dev_complete_discard(struct ocf_io *io, int error)
+{
+	struct bio *bio = io->priv1;
+
+	CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(error));
+	ocf_io_put(io);
+}
+
+static void _blockdev_handle_discard(ocf_core_t core, struct bio *bio)
 {
-	ocf_core_t core = private;
 	ocf_cache_t cache = ocf_core_get_cache(core);
 	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
 	struct ocf_io *io;
@@ -689,105 +766,89 @@ static void _blockdev_make_request_discard(struct casdsk_disk *dsk,
 		return;
 	}
 
-	ocf_io_set_cmpl(io, bio, NULL, block_dev_complete_bio_discard);
+	ocf_io_set_cmpl(io, bio, NULL, block_dev_complete_discard);
 
 	ocf_core_submit_discard(io);
 }
 
-static int _blockdev_make_request_fast(struct casdsk_disk *dsk,
-		struct request_queue *q, struct bio *bio, void *private)
+static void _blockdev_handle_bio_noflush(ocf_core_t core, struct bio *bio)
 {
-	ocf_core_t core;
-	ocf_cache_t cache;
-	struct cache_priv *cache_priv;
-	struct ocf_io *io;
-	struct blk_data *data;
-	int ret;
+	if (CAS_IS_DISCARD(bio))
+		_blockdev_handle_discard(core, bio);
+	else
+		_blockdev_handle_data(core, bio);
+}
 
-	BUG_ON(!private);
-	core = private;
-	cache = ocf_core_get_cache(core);
-	cache_priv = ocf_cache_get_priv(cache);
+static void block_dev_complete_flush(struct ocf_io *io, int error)
+{
+	struct bio *bio = io->priv1;
+	ocf_core_t core = io->priv2;
+
+	ocf_io_put(io);
+
+	if (CAS_BIO_BISIZE(bio) == 0 || error) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+				CAS_ERRNO_TO_BLK_STS(error));
+		return;
+	}
 
 	if (in_interrupt())
-		return CASDSK_BIO_NOT_HANDLED;
+		_blockdev_defer_bio(core, bio, _blockdev_handle_bio_noflush);
+	else
+		_blockdev_handle_bio_noflush(core, bio);
+}
 
-	if (_blkdev_can_hndl_bio(bio))
-		return CASDSK_BIO_HANDLED;
-
-	if (_blkdev_is_flush_fua_bio(bio))
-		return CASDSK_BIO_NOT_HANDLED;
-
-	if (CAS_IS_DISCARD(bio)) {
-		_blockdev_make_request_discard(dsk, q, bio, private);
-		return CASDSK_BIO_HANDLED;
-	}
-
-	if (unlikely(CAS_BIO_BISIZE(bio) == 0)) {
-		CAS_PRINT_RL(KERN_ERR
-			"Not able to handle empty BIO, flags = "
-			CAS_BIO_OP_FLAGS_FORMAT "\n",  CAS_BIO_OP_FLAGS(bio));
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
-		return CASDSK_BIO_HANDLED;
-	}
-
-	data = cas_alloc_blk_data(bio_segments(bio), GFP_NOIO);
-	if (!data) {
-		CAS_PRINT_RL(KERN_CRIT "BIO data vector allocation error\n");
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
-		return CASDSK_BIO_HANDLED;
-	}
-
-	_blockdev_set_bio_data(data, bio);
-
-	data->master_io_req = bio;
+static void _blkdev_handle_flush(ocf_core_t core, struct bio *bio)
+{
+	struct ocf_io *io;
+	ocf_cache_t cache = ocf_core_get_cache(core);
+	struct cache_priv *cache_priv = ocf_cache_get_priv(cache);
 
 	io = ocf_core_new_io(core, cache_priv->io_queues[smp_processor_id()],
-			CAS_BIO_BISECTOR(bio) << SECTOR_SHIFT,
-			CAS_BIO_BISIZE(bio), (bio_data_dir(bio) == READ) ?
-					OCF_READ : OCF_WRITE,
-			cas_cls_classify(cache, bio), 0);
-
+			0, 0, OCF_WRITE, 0, CAS_SET_FLUSH(0));
 	if (!io) {
-		printk(KERN_CRIT "Out of memory. Ending IO processing.\n");
-		cas_free_blk_data(data);
+		CAS_PRINT_RL(KERN_CRIT
+			"Out of memory. Ending IO processing.\n");
 		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-ENOMEM));
-		return CASDSK_BIO_HANDLED;
+		return;
 	}
 
-	ret = ocf_io_set_data(io, data, 0);
-	if (ret < 0) {
-		ocf_io_put(io);
-		cas_free_blk_data(data);
-		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EINVAL));
-		return CASDSK_BIO_HANDLED;
+	ocf_io_set_cmpl(io, bio, core, block_dev_complete_flush);
+
+	ocf_core_submit_flush(io);
+}
+
+static void _blockdev_handle_bio(ocf_core_t core, struct bio *bio)
+{
+	if (CAS_IS_SET_FLUSH(CAS_BIO_OP_FLAGS(bio)))
+		_blkdev_handle_flush(core, bio);
+	else
+		_blockdev_handle_bio_noflush(core, bio);
+}
+
+static void _blockdev_submit_bio(struct casdsk_disk *dsk,
+		struct bio *bio, void *private)
+{
+	ocf_core_t core = private;
+
+	BUG_ON(!core);
+
+	if (_blkdev_can_hndl_bio(bio)) {
+		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio),
+				CAS_ERRNO_TO_BLK_STS(-ENOTSUPP));
+		return;
 	}
 
-	ocf_io_set_cmpl(io, NULL, NULL, block_dev_complete_bio_fast);
-	ocf_io_set_start(io, block_dev_start_bio_fast);
-
-	ret = ocf_core_submit_io_fast(io);
-	if (ret < 0)
-		goto err;
-
-	return CASDSK_BIO_HANDLED;
-
-err:
-	/*
-	 * - Not able to processed fast path for this BIO,
-	 * - Cleanup current request
-	 * - Put it to the IO scheduler
-	 */
-	ocf_io_put(io);
-	cas_free_blk_data(data);
-
-	return CASDSK_BIO_NOT_HANDLED;
+	if (in_interrupt())
+		_blockdev_defer_bio(core, bio, _blockdev_handle_bio);
+	else
+		_blockdev_handle_bio(core, bio);
 }
 
 static struct casdsk_exp_obj_ops _blockdev_exp_obj_ops = {
 	.set_geometry = _blockdev_set_geometry,
-	.make_request_fn = _blockdev_make_request_fast,
 	.queue_rq_fn = _block_dev_queue_request,
+	.submit_bio = _blockdev_submit_bio,
 	.pending_rq_inc = _blockdev_pending_req_inc,
 	.pending_rq_dec = _blockdev_pending_req_dec,
 };
@@ -866,10 +927,23 @@ int block_dev_create_exported_object(ocf_core_t core)
 		return 0;
 	}
 
+	bvol->expobj_wq = alloc_workqueue("expobj_wq%s-%s",
+			WQ_MEM_RECLAIM | WQ_HIGHPRI, 0,
+			get_cache_id_string(cache),
+			get_core_id_string(core));
+	if (!bvol->expobj_wq) {
+		result = -ENOMEM;
+		goto end;
+	}
+
 	result = casdisk_functions.casdsk_exp_obj_create(dsk, dev_name,
 			THIS_MODULE, &_blockdev_exp_obj_ops);
-	if (!result)
-		bvol->expobj_valid = true;
+	if (result) {
+		destroy_workqueue(bvol->expobj_wq);
+		goto end;
+	}
+
+	bvol->expobj_valid = true;
 
 end:
 	if (result) {
@@ -899,6 +973,8 @@ int block_dev_destroy_exported_object(ocf_core_t core)
 	if (!bvol->expobj_valid)
 		return 0;
 
+	destroy_workqueue(bvol->expobj_wq);
+
 	ret = casdisk_functions.casdsk_exp_obj_lock(bvol->dsk);
 	if (ret) {
 		if (-EBUSY == ret)
@@ -907,11 +983,11 @@ int block_dev_destroy_exported_object(ocf_core_t core)
 	}
 
 	ret = casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
-	casdisk_functions.casdsk_exp_obj_unlock(bvol->dsk);
-
 	if (!ret)
 		bvol->expobj_valid = false;
 
+	casdisk_functions.casdsk_exp_obj_unlock(bvol->dsk);
+
 	return ret;
 }
 
@@ -954,6 +1030,7 @@ static int _block_dev_stop_exported_object(ocf_core_t core, void *cntx)
 {
 	struct bd_object *bvol = bd_object(
 			ocf_core_get_volume(core));
+	int ret;
 
 	if (bvol->expobj_valid) {
 		BUG_ON(!bvol->expobj_locked);
@@ -961,8 +1038,9 @@ static int _block_dev_stop_exported_object(ocf_core_t core, void *cntx)
 		printk(KERN_INFO "Stopping device %s\n",
 			casdisk_functions.casdsk_exp_obj_get_gendisk(bvol->dsk)->disk_name);
 
-		casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
-		bvol->expobj_valid = false;
+		ret = casdisk_functions.casdsk_exp_obj_destroy(bvol->dsk);
+		if (!ret)
+			bvol->expobj_valid = false;
 	}
 
 	if (bvol->expobj_locked) {
diff --git a/modules/cas_disk/cas_disk.h b/modules/cas_disk/cas_disk.h
index bb70d2a..78aecfb 100644
--- a/modules/cas_disk/cas_disk.h
+++ b/modules/cas_disk/cas_disk.h
@@ -11,13 +11,10 @@
 /**
  * Version of cas_disk interface
  */
-#define CASDSK_IFACE_VERSION 2
+#define CASDSK_IFACE_VERSION 3
 
 struct casdsk_disk;
 
-#define CASDSK_BIO_NOT_HANDLED 0
-#define CASDSK_BIO_HANDLED 1
-
 struct casdsk_exp_obj_ops {
 
 	/**
@@ -41,14 +38,11 @@ struct casdsk_exp_obj_ops {
 	int (*set_geometry)(struct casdsk_disk *dsk, void *private);
 
 	/**
-	 * @brief make_request_fn of exported object (top) block device.
+	 * @brief submit_bio of exported object (top) block device.
 	 * Called by cas_disk when cas_disk device is in attached mode.
 	 *
-	 * @return casdsk_BIO_HANDLED when bio was handled.
-	 * Otherwise casdsk_BIO_NOT_HANDLED. In this case bio will be submitted
-	 * to I/O scheduler and should be handled by request_fn.
 	 */
-	int (*make_request_fn)(struct casdsk_disk *dsk, struct request_queue *q,
+	void (*submit_bio)(struct casdsk_disk *dsk,
 			       struct bio *bio, void *private);
 
 	/**
diff --git a/modules/cas_disk/cas_disk_defs.h b/modules/cas_disk/cas_disk_defs.h
index b8ced1f..24ae5a2 100644
--- a/modules/cas_disk/cas_disk_defs.h
+++ b/modules/cas_disk/cas_disk_defs.h
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/kobject.h>
+#include <linux/blkdev.h>
 
 struct casdsk_stored_config {
 	size_t n_blobs;
diff --git a/modules/cas_disk/exp_obj.c b/modules/cas_disk/exp_obj.c
index 7842b4b..bfd309b 100644
--- a/modules/cas_disk/exp_obj.c
+++ b/modules/cas_disk/exp_obj.c
@@ -67,17 +67,9 @@ void casdsk_deinit_exp_objs(void)
 }
 
 static inline void _casdsk_exp_obj_handle_bio_att(struct casdsk_disk *dsk,
-						struct request_queue *q,
 						struct bio *bio)
 {
-	int status = CASDSK_BIO_NOT_HANDLED;
-
-	if (likely(dsk->exp_obj->ops->make_request_fn))
-		status = dsk->exp_obj->ops->
-				make_request_fn(dsk, q, bio, dsk->private);
-
-	if (status == CASDSK_BIO_NOT_HANDLED)
-		cas_call_default_mk_request_fn(dsk->exp_obj->mk_rq_fn, q, bio);
+	dsk->exp_obj->ops->submit_bio(dsk, bio, dsk->private);
 }
 
 CAS_DECLARE_BLOCK_CALLBACK(_casdsk_exp_obj_bio_pt_io, struct bio *bio,
@@ -102,7 +94,6 @@ CAS_DECLARE_BLOCK_CALLBACK(_casdsk_exp_obj_bio_pt_io, struct bio *bio,
 }
 
 static inline void _casdsk_exp_obj_handle_bio_pt(struct casdsk_disk *dsk,
-					       struct request_queue *q,
 					       struct bio *bio)
 {
 	struct bio *cloned_bio;
@@ -133,13 +124,12 @@ static inline void _casdsk_exp_obj_handle_bio_pt(struct casdsk_disk *dsk,
 }
 
 static inline void _casdsk_exp_obj_handle_bio(struct casdsk_disk *dsk,
-					    struct request_queue *q,
 					    struct bio *bio)
 {
 	if (likely(casdsk_disk_is_attached(dsk)))
-		_casdsk_exp_obj_handle_bio_att(dsk, q, bio);
+		_casdsk_exp_obj_handle_bio_att(dsk, bio);
 	else if (casdsk_disk_is_pt(dsk))
-		_casdsk_exp_obj_handle_bio_pt(dsk, q, bio);
+		_casdsk_exp_obj_handle_bio_pt(dsk, bio);
 	else if (casdsk_disk_is_shutdown(dsk))
 		CAS_BIO_ENDIO(bio, CAS_BIO_BISIZE(bio), CAS_ERRNO_TO_BLK_STS(-EIO));
 	else
@@ -176,26 +166,29 @@ retry:
 	return cpu;
 }
 
-static MAKE_RQ_RET_TYPE _casdsk_exp_obj_make_rq_fn(struct request_queue *q,
-						 struct bio *bio)
+static MAKE_RQ_RET_TYPE _casdsk_exp_obj_submit_bio(struct bio *bio)
 {
 	struct casdsk_disk *dsk;
 	unsigned int cpu;
 
 	BUG_ON(!bio);
-	BUG_ON(!q);
-	BUG_ON(!q->queuedata);
-	dsk = q->queuedata;
+	dsk = CAS_BIO_GET_GENDISK(bio)->private_data;
 
 	cpu = _casdsk_exp_obj_begin_rq(dsk);
 
-	_casdsk_exp_obj_handle_bio(dsk, q, bio);
+	_casdsk_exp_obj_handle_bio(dsk, bio);
 
 	_casdsk_exp_obj_end_rq(dsk, cpu);
 
 	KRETURN(0);
 }
 
+static MAKE_RQ_RET_TYPE _casdsk_exp_obj_make_rq_fn(struct request_queue *q,
+						 struct bio *bio)
+{
+	return _casdsk_exp_obj_submit_bio(bio);
+}
+
 static int _casdsk_get_next_part_no(struct block_device *bd)
 {
 	int part_no = 0;
@@ -369,6 +362,7 @@ static void _casdsk_exp_obj_clear_dev_t(struct casdsk_disk *dsk)
 
 static const struct block_device_operations _casdsk_exp_obj_ops = {
 	.owner = THIS_MODULE,
+	CAS_SET_SUBMIT_BIO(_casdsk_exp_obj_submit_bio)
 };
 
 static int casdsk_exp_obj_alloc(struct casdsk_disk *dsk)
@@ -611,7 +605,6 @@ int casdsk_exp_obj_create(struct casdsk_disk *dsk, const char *dev_name,
 	gd->private_data = dsk;
 	strlcpy(gd->disk_name, exp_obj->dev_name, sizeof(gd->disk_name));
 
-	dsk->exp_obj->mk_rq_fn = cas_get_default_mk_request_fn(queue);
 	cas_blk_queue_make_request(queue, _casdsk_exp_obj_make_rq_fn);
 
 	if (exp_obj->ops->set_geometry) {
diff --git a/modules/cas_disk/exp_obj.h b/modules/cas_disk/exp_obj.h
index ccd050f..616ee71 100644
--- a/modules/cas_disk/exp_obj.h
+++ b/modules/cas_disk/exp_obj.h
@@ -28,8 +28,6 @@ struct casdsk_exp_obj {
 
 	struct casdsk_exp_obj_ops *ops;
 
-	make_request_fn *mk_rq_fn;
-
 	const char *dev_name;
 	struct kobject kobj;