diff --git a/block/Makefile.objs b/block/Makefile.objs
index 7a81892..ae11605 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -6,7 +6,7 @@
 block-obj-$(CONFIG_VVFAT) += vvfat.o
 block-obj-$(CONFIG_DMG) += dmg.o
 
-block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o qcow2-bitmap.o
+block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o qcow2-bitmap.o qcow2-threads.o
 block-obj-$(CONFIG_QED) += qed.o qed-l2-cache.o qed-table.o qed-cluster.o
 block-obj-$(CONFIG_QED) += qed-check.o
 block-obj-y += vhdx.o vhdx-endian.o vhdx-log.o
diff --git a/block/qcow2-threads.c b/block/qcow2-threads.c
new file mode 100644
index 0000000..85b8034
--- /dev/null
+++ b/block/qcow2-threads.c
@@ -0,0 +1,201 @@
+/*
+ * Threaded data processing for Qcow2: compression, encryption
+ *
+ * Copyright (c) 2004-2006 Fabrice Bellard
+ * Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+
+#define ZLIB_CONST
+#include <zlib.h>
+
+#include "qcow2.h"
+#include "block/thread-pool.h"
+
+#define MAX_COMPRESS_THREADS 4
+
+typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
+                                     const void *src, size_t src_size);
+typedef struct Qcow2CompressData {
+    void *dest;
+    size_t dest_size;
+    const void *src;
+    size_t src_size;
+    ssize_t ret;
+
+    Qcow2CompressFunc func;
+} Qcow2CompressData;
+
+/*
+ * qcow2_compress()
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ *          -ENOMEM destination buffer is not enough to store compressed data
+ *          -EIO    on any other error
+ */
+static ssize_t qcow2_compress(void *dest, size_t dest_size,
+                              const void *src, size_t src_size)
+{
+    ssize_t ret;
+    z_stream strm;
+
+    /* best compression, small window, no zlib header */
+    memset(&strm, 0, sizeof(strm));
+    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+                       -12, 9, Z_DEFAULT_STRATEGY);
+    if (ret != Z_OK) {
+        return -EIO;
+    }
+
+    /*
+     * strm.next_in is not const in old zlib versions, such as those used on
+     * OpenBSD/NetBSD, so cast the const away
+     */
+    strm.avail_in = src_size;
+    strm.next_in = (void *) src;
+    strm.avail_out = dest_size;
+    strm.next_out = dest;
+
+    ret = deflate(&strm, Z_FINISH);
+    if (ret == Z_STREAM_END) {
+        ret = dest_size - strm.avail_out;
+    } else {
+        ret = (ret == Z_OK ? -ENOMEM : -EIO);
+    }
+
+    deflateEnd(&strm);
+
+    return ret;
+}
+
+/*
+ * qcow2_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes.
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ *          -1 on fail
+ */
+static ssize_t qcow2_decompress(void *dest, size_t dest_size,
+                                const void *src, size_t src_size)
+{
+    int ret = 0;
+    z_stream strm;
+
+    memset(&strm, 0, sizeof(strm));
+    strm.avail_in = src_size;
+    strm.next_in = (void *) src;
+    strm.avail_out = dest_size;
+    strm.next_out = dest;
+
+    ret = inflateInit2(&strm, -12);
+    if (ret != Z_OK) {
+        return -1;
+    }
+
+    ret = inflate(&strm, Z_FINISH);
+    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
+        /*
+         * We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
+         * @src buffer may be processed partly (because in qcow2 we know size of
+         * compressed data with precision of one sector)
+         */
+        ret = -1;
+    }
+
+    inflateEnd(&strm);
+
+    return ret;
+}
+
+static int qcow2_compress_pool_func(void *opaque)
+{
+    Qcow2CompressData *data = opaque;
+
+    data->ret = data->func(data->dest, data->dest_size,
+                           data->src, data->src_size);
+
+    return 0;
+}
+
+static void qcow2_compress_complete(void *opaque, int ret)
+{
+    qemu_coroutine_enter(opaque);
+}
+
+static ssize_t coroutine_fn
+qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                     const void *src, size_t src_size, Qcow2CompressFunc func)
+{
+    BDRVQcow2State *s = bs->opaque;
+    BlockAIOCB *acb;
+    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
+    Qcow2CompressData arg = {
+        .dest = dest,
+        .dest_size = dest_size,
+        .src = src,
+        .src_size = src_size,
+        .func = func,
+    };
+
+    while (s->nb_compress_threads >= MAX_COMPRESS_THREADS) {
+        qemu_co_queue_wait(&s->compress_wait_queue, NULL);
+    }
+
+    s->nb_compress_threads++;
+    acb = thread_pool_submit_aio(pool, qcow2_compress_pool_func, &arg,
+                                 qcow2_compress_complete,
+                                 qemu_coroutine_self());
+
+    if (!acb) {
+        s->nb_compress_threads--;
+        return -EINVAL;
+    }
+    qemu_coroutine_yield();
+    s->nb_compress_threads--;
+    qemu_co_queue_next(&s->compress_wait_queue);
+
+    return arg.ret;
+}
+
+ssize_t coroutine_fn
+qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                  const void *src, size_t src_size)
+{
+    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
+                                qcow2_compress);
+}
+
+ssize_t coroutine_fn
+qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
+                    const void *src, size_t src_size)
+{
+    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
+                                qcow2_decompress);
+}
diff --git a/block/qcow2.c b/block/qcow2.c
index 38bf729..a8c4b11 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -24,9 +24,6 @@
 
 #include "qemu/osdep.h"
 
-#define ZLIB_CONST
-#include <zlib.h>
-
 #include "block/qdict.h"
 #include "sysemu/block-backend.h"
 #include "qemu/module.h"
@@ -43,7 +40,6 @@
 #include "qapi/qobject-input-visitor.h"
 #include "qapi/qapi-visit-block-core.h"
 #include "crypto.h"
-#include "block/thread-pool.h"
 
 /*
   Differences with QCOW:
@@ -3920,171 +3916,6 @@
     return ret;
 }
 
-/*
- * qcow2_compress()
- *
- * @dest - destination buffer, @dest_size bytes
- * @src - source buffer, @src_size bytes
- *
- * Returns: compressed size on success
- *          -ENOMEM destination buffer is not enough to store compressed data
- *          -EIO    on any other error
- */
-static ssize_t qcow2_compress(void *dest, size_t dest_size,
-                              const void *src, size_t src_size)
-{
-    ssize_t ret;
-    z_stream strm;
-
-    /* best compression, small window, no zlib header */
-    memset(&strm, 0, sizeof(strm));
-    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
-                       -12, 9, Z_DEFAULT_STRATEGY);
-    if (ret != Z_OK) {
-        return -EIO;
-    }
-
-    /* strm.next_in is not const in old zlib versions, such as those used on
-     * OpenBSD/NetBSD, so cast the const away */
-    strm.avail_in = src_size;
-    strm.next_in = (void *) src;
-    strm.avail_out = dest_size;
-    strm.next_out = dest;
-
-    ret = deflate(&strm, Z_FINISH);
-    if (ret == Z_STREAM_END) {
-        ret = dest_size - strm.avail_out;
-    } else {
-        ret = (ret == Z_OK ? -ENOMEM : -EIO);
-    }
-
-    deflateEnd(&strm);
-
-    return ret;
-}
-
-/*
- * qcow2_decompress()
- *
- * Decompress some data (not more than @src_size bytes) to produce exactly
- * @dest_size bytes.
- *
- * @dest - destination buffer, @dest_size bytes
- * @src - source buffer, @src_size bytes
- *
- * Returns: 0 on success
- *          -1 on fail
- */
-static ssize_t qcow2_decompress(void *dest, size_t dest_size,
-                                const void *src, size_t src_size)
-{
-    int ret = 0;
-    z_stream strm;
-
-    memset(&strm, 0, sizeof(strm));
-    strm.avail_in = src_size;
-    strm.next_in = (void *) src;
-    strm.avail_out = dest_size;
-    strm.next_out = dest;
-
-    ret = inflateInit2(&strm, -12);
-    if (ret != Z_OK) {
-        return -1;
-    }
-
-    ret = inflate(&strm, Z_FINISH);
-    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
-        /* We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
-         * @src buffer may be processed partly (because in qcow2 we know size of
-         * compressed data with precision of one sector) */
-        ret = -1;
-    }
-
-    inflateEnd(&strm);
-
-    return ret;
-}
-
-#define MAX_COMPRESS_THREADS 4
-
-typedef ssize_t (*Qcow2CompressFunc)(void *dest, size_t dest_size,
-                                     const void *src, size_t src_size);
-typedef struct Qcow2CompressData {
-    void *dest;
-    size_t dest_size;
-    const void *src;
-    size_t src_size;
-    ssize_t ret;
-
-    Qcow2CompressFunc func;
-} Qcow2CompressData;
-
-static int qcow2_compress_pool_func(void *opaque)
-{
-    Qcow2CompressData *data = opaque;
-
-    data->ret = data->func(data->dest, data->dest_size,
-                           data->src, data->src_size);
-
-    return 0;
-}
-
-static void qcow2_compress_complete(void *opaque, int ret)
-{
-    qemu_coroutine_enter(opaque);
-}
-
-static ssize_t coroutine_fn
-qcow2_co_do_compress(BlockDriverState *bs, void *dest, size_t dest_size,
-                     const void *src, size_t src_size, Qcow2CompressFunc func)
-{
-    BDRVQcow2State *s = bs->opaque;
-    BlockAIOCB *acb;
-    ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
-    Qcow2CompressData arg = {
-        .dest = dest,
-        .dest_size = dest_size,
-        .src = src,
-        .src_size = src_size,
-        .func = func,
-    };
-
-    while (s->nb_compress_threads >= MAX_COMPRESS_THREADS) {
-        qemu_co_queue_wait(&s->compress_wait_queue, NULL);
-    }
-
-    s->nb_compress_threads++;
-    acb = thread_pool_submit_aio(pool, qcow2_compress_pool_func, &arg,
-                                 qcow2_compress_complete,
-                                 qemu_coroutine_self());
-
-    if (!acb) {
-        s->nb_compress_threads--;
-        return -EINVAL;
-    }
-    qemu_coroutine_yield();
-    s->nb_compress_threads--;
-    qemu_co_queue_next(&s->compress_wait_queue);
-
-    return arg.ret;
-}
-
-static ssize_t coroutine_fn
-qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
-                  const void *src, size_t src_size)
-{
-    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
-                                qcow2_compress);
-}
-
-static ssize_t coroutine_fn
-qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
-                    const void *src, size_t src_size)
-{
-    return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
-                                qcow2_decompress);
-}
-
 /* XXX: put compressed sectors first, then all the cluster aligned
    tables to avoid losing bytes in alignment */
 static coroutine_fn int
diff --git a/block/qcow2.h b/block/qcow2.h
index c2b0e95..8207ed3 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -738,4 +738,11 @@
                                           const char *name,
                                           Error **errp);
 
+ssize_t coroutine_fn
+qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
+                  const void *src, size_t src_size);
+ssize_t coroutine_fn
+qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
+                    const void *src, size_t src_size);
+
 #endif