diff --git a/debian/changelog b/debian/changelog
index c8b8e5e..e38a77b 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+pve-qemu-kvm (7.1.0-4+vitastor4) bullseye; urgency=medium
+
+  * Improve performance by adding io_uring support
+  * Fix compatibility with iothread
+
+ -- Vitaliy Filippov <vitalif@yourcmc.ru>  Tue, 18 Jul 2023 02:22:28 +0300
+
 pve-qemu-kvm (7.1.0-4+vitastor3) bullseye; urgency=medium
 
   * Add bdrv_co_block_status implementation for QCOW2 export support
diff --git a/debian/control b/debian/control
index 45e9ab9..2fd2435 100644
--- a/debian/control
+++ b/debian/control
@@ -62,6 +62,7 @@ Depends: ceph-common (>= 0.48),
          libspice-server1 (>= 0.14.0~),
          libusb-1.0-0 (>= 1.0.17-1),
          libusbredirparser1 (>= 0.6-2),
+         vitastor-client (>= 0.9.4),
          libuuid1,
          ${misc:Depends},
          ${shlibs:Depends},
diff --git a/debian/patches/pve-qemu-7.1-vitastor.patch b/debian/patches/pve-qemu-7.1-vitastor.patch
index 661eb5e..21eaa92 100644
--- a/debian/patches/pve-qemu-7.1-vitastor.patch
+++ b/debian/patches/pve-qemu-7.1-vitastor.patch
@@ -171,7 +171,7 @@ Index: a/block/vitastor.c
 ===================================================================
 --- /dev/null
 +++ a/block/vitastor.c
-@@ -0,0 +1,797 @@
+@@ -0,0 +1,1017 @@
 +// Copyright (c) Vitaliy Filippov, 2019+
 +// License: VNPL-1.1 or GNU GPL-2.0+ (see README.md for details)
 +
@@ -183,6 +183,9 @@ Index: a/block/vitastor.c
 +#endif
 +#include "qemu/osdep.h"
 +#include "qemu/main-loop.h"
++#if QEMU_VERSION_MAJOR >= 8
++#include "block/block-io.h"
++#endif
 +#include "block/block_int.h"
 +#include "qapi/error.h"
 +#include "qapi/qmp/qdict.h"
@@ -206,6 +209,11 @@ Index: a/block/vitastor.c
 +#define qdict_put_str(options, name, value) qdict_put_obj(options, name, QOBJECT(qstring_from_str(value)))
 +#define qobject_unref QDECREF
 +#endif
++#if QEMU_VERSION_MAJOR == 4 && QEMU_VERSION_MINOR >= 2 || QEMU_VERSION_MAJOR > 4
++#include "sysemu/replay.h"
++#else
++#include "sysemu/sysemu.h"
++#endif
 +
 +#include "vitastor_c.h"
 +
@@ -219,9 +227,13 @@ Index: a/block/vitastor.c
 +}
 +#endif
 +
++typedef struct VitastorFdData VitastorFdData;
++
 +typedef struct VitastorClient
 +{
 +    void *proxy;
++    int uring_eventfd;
++
 +    void *watch;
 +    char *config_path;
 +    char *etcd_host;
@@ -238,12 +250,24 @@ Index: a/block/vitastor.c
 +    int rdma_gid_index;
 +    int rdma_mtu;
 +    QemuMutex mutex;
++    AioContext *ctx;
++    VitastorFdData **fds;
++    int fd_count, fd_alloc;
++    int bh_uring_scheduled;
 +
 +    uint64_t last_bitmap_inode, last_bitmap_offset, last_bitmap_len;
 +    uint32_t last_bitmap_granularity;
 +    uint8_t *last_bitmap;
 +} VitastorClient;
 +
++typedef struct VitastorFdData
++{
++    VitastorClient *cli;
++    int fd;
++    IOHandler *fd_read, *fd_write;
++    void *opaque;
++} VitastorFdData;
++
 +typedef struct VitastorRPC
 +{
 +    BlockDriverState *bs;
@@ -254,10 +278,21 @@ Index: a/block/vitastor.c
 +    uint64_t inode, offset, len;
 +    uint32_t bitmap_granularity;
 +    uint8_t *bitmap;
++#if QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR < 8
++    QEMUBH *bh;
++#endif
 +} VitastorRPC;
 +
++#if QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR < 8
++typedef struct VitastorBH
++{
++    VitastorClient *cli;
++    QEMUBH *bh;
++} VitastorBH;
++#endif
++
 +static void vitastor_co_init_task(BlockDriverState *bs, VitastorRPC *task);
-+static void vitastor_co_generic_bh_cb(void *opaque, long retval);
++static void vitastor_co_generic_cb(void *opaque, long retval);
 +static void vitastor_co_read_cb(void *opaque, long retval, uint64_t version);
 +static void vitastor_close(BlockDriverState *bs);
 +
@@ -373,6 +408,57 @@ Index: a/block/vitastor.c
 +    return;
 +}
 +
++#if defined VITASTOR_C_API_VERSION && VITASTOR_C_API_VERSION >= 2
++static void vitastor_uring_handler(void *opaque)
++{
++    VitastorClient *client = (VitastorClient*)opaque;
++    qemu_mutex_lock(&client->mutex);
++    client->bh_uring_scheduled = 0;
++    do
++    {
++        vitastor_c_uring_handle_events(client->proxy);
++    } while (vitastor_c_uring_has_work(client->proxy));
++    qemu_mutex_unlock(&client->mutex);
++}
++
++#if QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR < 8
++static void vitastor_bh_uring_handler(void *opaque)
++{
++    VitastorBH *vbh = opaque;
++    vitastor_bh_handler(vbh->cli);
++    qemu_bh_delete(vbh->bh);
++    free(vbh);
++}
++#endif
++
++static void vitastor_schedule_uring_handler(VitastorClient *client)
++{
++    void *opaque = client;
++    if (client->uring_eventfd >= 0 && !client->bh_uring_scheduled)
++    {
++        client->bh_uring_scheduled = 1;
++#if QEMU_VERSION_MAJOR > 4 || QEMU_VERSION_MAJOR == 4 && QEMU_VERSION_MINOR >= 2
++        replay_bh_schedule_oneshot_event(client->ctx, vitastor_uring_handler, opaque);
++#elif QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR >= 8
++        aio_bh_schedule_oneshot(client->ctx, vitastor_uring_handler, opaque);
++#else
++        VitastorBH *vbh = (VitastorBH*)malloc(sizeof(VitastorBH));
++        vbh->cli = client;
++#if QEMU_VERSION_MAJOR >= 2
++        vbh->bh = aio_bh_new(bdrv_get_aio_context(task->bs), vitastor_bh_uring_handler, vbh);
++#else
++        vbh->bh = qemu_bh_new(vitastor_bh_uring_handler, vbh);
++#endif
++        qemu_bh_schedule(vbh->bh);
++#endif
++    }
++}
++#else
++static void vitastor_schedule_uring_handler(VitastorClient *client)
++{
++}
++#endif
++
 +static void coroutine_fn vitastor_co_get_metadata(VitastorRPC *task)
 +{
 +    BlockDriverState *bs = task->bs;
@@ -380,7 +466,8 @@ Index: a/block/vitastor.c
 +    task->co = qemu_coroutine_self();
 +
 +    qemu_mutex_lock(&client->mutex);
-+    vitastor_c_watch_inode(client->proxy, client->image, vitastor_co_generic_bh_cb, task);
++    vitastor_c_watch_inode(client->proxy, client->image, vitastor_co_generic_cb, task);
++    vitastor_schedule_uring_handler(client);
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task->complete)
@@ -389,13 +476,32 @@ Index: a/block/vitastor.c
 +    }
 +}
 +
-+static void vitastor_aio_set_fd_handler(void *ctx, int fd, int unused1, IOHandler *fd_read, IOHandler *fd_write, void *unused2, void *opaque)
++static void vitastor_aio_fd_read(void *fddv)
++{
++    VitastorFdData *fdd = (VitastorFdData*)fddv;
++    qemu_mutex_lock(&fdd->cli->mutex);
++    fdd->fd_read(fdd->opaque);
++    vitastor_schedule_uring_handler(fdd->cli);
++    qemu_mutex_unlock(&fdd->cli->mutex);
++}
++
++static void vitastor_aio_fd_write(void *fddv)
++{
++    VitastorFdData *fdd = (VitastorFdData*)fddv;
++    qemu_mutex_lock(&fdd->cli->mutex);
++    fdd->fd_write(fdd->opaque);
++    vitastor_schedule_uring_handler(fdd->cli);
++    qemu_mutex_unlock(&fdd->cli->mutex);
++}
++
++static void universal_aio_set_fd_handler(AioContext *ctx, int fd, IOHandler *fd_read, IOHandler *fd_write, void *opaque)
 +{
 +    aio_set_fd_handler(ctx, fd,
 +#if QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR >= 5 || QEMU_VERSION_MAJOR >= 3
 +        0 /*is_external*/,
 +#endif
-+        fd_read, fd_write,
++        fd_read,
++        fd_write,
 +#if QEMU_VERSION_MAJOR == 1 && QEMU_VERSION_MINOR <= 6 || QEMU_VERSION_MAJOR < 1
 +        NULL /*io_flush*/,
 +#endif
@@ -408,6 +514,53 @@ Index: a/block/vitastor.c
 +        opaque);
 +}
 +
++static void vitastor_aio_set_fd_handler(void *vcli, int fd, int unused1, IOHandler *fd_read, IOHandler *fd_write, void *unused2, void *opaque)
++{
++    VitastorClient *client = (VitastorClient*)vcli;
++    VitastorFdData *fdd = NULL;
++    int i;
++    for (i = 0; i < client->fd_count; i++)
++    {
++        if (client->fds[i]->fd == fd)
++        {
++            if (fd_read || fd_write)
++            {
++                fdd = client->fds[i];
++                fdd->opaque = opaque;
++                fdd->fd_read = fd_read;
++                fdd->fd_write = fd_write;
++            }
++            else
++            {
++                for (int j = i+1; j < client->fd_count; j++)
++                    client->fds[j-1] = client->fds[j];
++                client->fd_count--;
++            }
++            break;
++        }
++    }
++    if ((fd_read || fd_write) && !fdd)
++    {
++        fdd = (VitastorFdData*)malloc(sizeof(VitastorFdData));
++        fdd->cli = client;
++        fdd->fd = fd;
++        fdd->fd_read = fd_read;
++        fdd->fd_write = fd_write;
++        fdd->opaque = opaque;
++        if (client->fd_count >= client->fd_alloc)
++        {
++            client->fd_alloc = client->fd_alloc*2;
++            if (client->fd_alloc < 16)
++                client->fd_alloc = 16;
++            client->fds = (VitastorFdData**)realloc(client->fds, sizeof(VitastorFdData*) * client->fd_alloc);
++        }
++        client->fds[client->fd_count++] = fdd;
++    }
++    universal_aio_set_fd_handler(
++        client->ctx, fd, fd_read ? vitastor_aio_fd_read : NULL, fd_write ? vitastor_aio_fd_write : NULL, fdd
++    );
++}
++
 +static int vitastor_file_open(BlockDriverState *bs, QDict *options, int flags, Error **errp)
 +{
 +    VitastorRPC task;
@@ -425,10 +578,36 @@ Index: a/block/vitastor.c
 +    client->rdma_port_num = qdict_get_try_int(options, "rdma-port-num", 0);
 +    client->rdma_gid_index = qdict_get_try_int(options, "rdma-gid-index", 0);
 +    client->rdma_mtu = qdict_get_try_int(options, "rdma-mtu", 0);
-+    client->proxy = vitastor_c_create_qemu(
-+        vitastor_aio_set_fd_handler, bdrv_get_aio_context(bs), client->config_path, client->etcd_host, client->etcd_prefix,
++    client->ctx = bdrv_get_aio_context(bs);
++#if defined VITASTOR_C_API_VERSION && VITASTOR_C_API_VERSION >= 2
++    client->proxy = vitastor_c_create_qemu_uring(
++        vitastor_aio_set_fd_handler, client, client->config_path, client->etcd_host, client->etcd_prefix,
 +        client->use_rdma, client->rdma_device, client->rdma_port_num, client->rdma_gid_index, client->rdma_mtu, 0
 +    );
++    if (!client->proxy)
++    {
++        fprintf(stderr, "vitastor: failed to create io_uring: %s - I/O will be slower\n", strerror(errno));
++        client->uring_eventfd = -1;
++#endif
++        client->proxy = vitastor_c_create_qemu(
++            vitastor_aio_set_fd_handler, client, client->config_path, client->etcd_host, client->etcd_prefix,
++            client->use_rdma, client->rdma_device, client->rdma_port_num, client->rdma_gid_index, client->rdma_mtu, 0
++        );
++#if defined VITASTOR_C_API_VERSION && VITASTOR_C_API_VERSION >= 2
++    }
++    else
++    {
++        client->uring_eventfd = vitastor_c_uring_register_eventfd(client->proxy);
++        if (client->uring_eventfd < 0)
++        {
++            fprintf(stderr, "vitastor: failed to create io_uring eventfd: %s\n", strerror(errno));
++            error_setg(errp, "failed to create io_uring eventfd");
++            vitastor_close(bs);
++            return -1;
++        }
++        universal_aio_set_fd_handler(client->ctx, client->uring_eventfd, vitastor_uring_handler, NULL, client);
++    }
++#endif
 +    image = client->image = g_strdup(qdict_get_try_str(options, "image"));
 +    client->readonly = (flags & BDRV_O_RDWR) ? 1 : 0;
 +    // Get image metadata (size and readonly flag) or just wait until the client is ready
@@ -442,7 +621,13 @@ Index: a/block/vitastor.c
 +    }
 +    else
 +    {
++#if QEMU_VERSION_MAJOR >= 8
++        aio_co_enter(bdrv_get_aio_context(bs), qemu_coroutine_create((void(*)(void*))vitastor_co_get_metadata, &task));
++#elif QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR >= 9 || QEMU_VERSION_MAJOR >= 3
 +        bdrv_coroutine_enter(bs, qemu_coroutine_create((void(*)(void*))vitastor_co_get_metadata, &task));
++#else
++        qemu_coroutine_enter(qemu_coroutine_create((void(*)(void*))vitastor_co_get_metadata, &task));
++#endif
 +        BDRV_POLL_WHILE(bs, !task.complete);
 +    }
 +    client->image = image;
@@ -502,6 +687,12 @@ Index: a/block/vitastor.c
 +{
 +    VitastorClient *client = bs->opaque;
 +    vitastor_c_destroy(client->proxy);
++    if (client->fds)
++    {
++        free(client->fds);
++        client->fds = NULL;
++        client->fd_alloc = client->fd_count = 0;
++    }
 +    qemu_mutex_destroy(&client->mutex);
 +    if (client->config_path)
 +        g_free(client->config_path);
@@ -618,25 +809,44 @@ Index: a/block/vitastor.c
 +    };
 +}
 +
-+static void vitastor_co_generic_bh_cb(void *opaque, long retval)
++static void vitastor_co_generic_bh_cb(void *opaque)
 +{
 +    VitastorRPC *task = opaque;
-+    task->ret = retval;
 +    task->complete = 1;
 +    if (qemu_coroutine_self() != task->co)
 +    {
 +#if QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR > 8
 +        aio_co_wake(task->co);
 +#else
++#if QEMU_VERSION_MAJOR == 2
++        qemu_bh_delete(task->bh);
++#endif
 +        qemu_coroutine_enter(task->co, NULL);
 +        qemu_aio_release(task);
 +#endif
 +    }
 +}
 +
++static void vitastor_co_generic_cb(void *opaque, long retval)
++{
++    VitastorRPC *task = opaque;
++    task->ret = retval;
++#if QEMU_VERSION_MAJOR > 4 || QEMU_VERSION_MAJOR == 4 && QEMU_VERSION_MINOR >= 2
++    replay_bh_schedule_oneshot_event(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++#elif QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR >= 8
++    aio_bh_schedule_oneshot(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++#elif QEMU_VERSION_MAJOR >= 2
++    task->bh = aio_bh_new(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++    qemu_bh_schedule(task->bh);
++#else
++    task->bh = qemu_bh_new(vitastor_co_generic_bh_cb, opaque);
++    qemu_bh_schedule(task->bh);
++#endif
++}
++
 +static void vitastor_co_read_cb(void *opaque, long retval, uint64_t version)
 +{
-+    vitastor_co_generic_bh_cb(opaque, retval);
++    vitastor_co_generic_cb(opaque, retval);
 +}
 +
 +static int coroutine_fn vitastor_co_preadv(BlockDriverState *bs,
@@ -655,6 +865,7 @@ Index: a/block/vitastor.c
 +    uint64_t inode = client->watch ? vitastor_c_inode_get_num(client->watch) : client->inode;
 +    qemu_mutex_lock(&client->mutex);
 +    vitastor_c_read(client->proxy, inode, offset, bytes, iov->iov, iov->niov, vitastor_co_read_cb, &task);
++    vitastor_schedule_uring_handler(client);
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -687,7 +898,8 @@ Index: a/block/vitastor.c
 +
 +    uint64_t inode = client->watch ? vitastor_c_inode_get_num(client->watch) : client->inode;
 +    qemu_mutex_lock(&client->mutex);
-+    vitastor_c_write(client->proxy, inode, offset, bytes, 0, iov->iov, iov->niov, vitastor_co_generic_bh_cb, &task);
++    vitastor_c_write(client->proxy, inode, offset, bytes, 0, iov->iov, iov->niov, vitastor_co_generic_cb, &task);
++    vitastor_schedule_uring_handler(client);
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -705,7 +917,6 @@ Index: a/block/vitastor.c
 +    VitastorRPC *task = opaque;
 +    VitastorClient *client = task->bs->opaque;
 +    task->ret = retval;
-+    task->complete = 1;
 +    if (retval >= 0)
 +    {
 +        task->bitmap = bitmap;
@@ -717,15 +928,17 @@ Index: a/block/vitastor.c
 +            client->last_bitmap = bitmap;
 +        }
 +    }
-+    if (qemu_coroutine_self() != task->co)
-+    {
-+#if QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR > 8
-+        aio_co_wake(task->co);
++#if QEMU_VERSION_MAJOR > 4 || QEMU_VERSION_MAJOR == 4 && QEMU_VERSION_MINOR >= 2
++    replay_bh_schedule_oneshot_event(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++#elif QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR >= 8
++    aio_bh_schedule_oneshot(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++#elif QEMU_VERSION_MAJOR >= 2
++    task->bh = aio_bh_new(bdrv_get_aio_context(task->bs), vitastor_co_generic_bh_cb, opaque);
++    qemu_bh_schedule(task->bh);
 +#else
-+        qemu_coroutine_enter(task->co, NULL);
-+        qemu_aio_release(task);
++    task->bh = qemu_bh_new(vitastor_co_generic_bh_cb, opaque);
++    qemu_bh_schedule(task->bh);
 +#endif
-+    }
 +}
 +
 +static int coroutine_fn vitastor_co_block_status(
@@ -766,6 +979,7 @@ Index: a/block/vitastor.c
 +        task.bitmap = client->last_bitmap = NULL;
 +        qemu_mutex_lock(&client->mutex);
 +        vitastor_c_read_bitmap(client->proxy, task.inode, task.offset, task.len, !client->skip_parents, vitastor_co_read_bitmap_cb, &task);
++        vitastor_schedule_uring_handler(client);
 +        qemu_mutex_unlock(&client->mutex);
 +        while (!task.complete)
 +        {
@@ -851,7 +1065,8 @@ Index: a/block/vitastor.c
 +    vitastor_co_init_task(bs, &task);
 +
 +    qemu_mutex_lock(&client->mutex);
-+    vitastor_c_sync(client->proxy, vitastor_co_generic_bh_cb, &task);
++    vitastor_c_sync(client->proxy, vitastor_co_generic_cb, &task);
++    vitastor_schedule_uring_handler(client);
 +    qemu_mutex_unlock(&client->mutex);
 +
 +    while (!task.complete)
@@ -906,8 +1121,13 @@ Index: a/block/vitastor.c
 +    .bdrv_parse_filename            = vitastor_parse_filename,
 +
 +    .bdrv_has_zero_init             = bdrv_has_zero_init_1,
++#if QEMU_VERSION_MAJOR >= 8
++    .bdrv_co_get_info               = vitastor_get_info,
++    .bdrv_co_getlength              = vitastor_getlength,
++#else
 +    .bdrv_get_info                  = vitastor_get_info,
 +    .bdrv_getlength                 = vitastor_getlength,
++#endif
 +#if QEMU_VERSION_MAJOR >= 3 || QEMU_VERSION_MAJOR == 2 && QEMU_VERSION_MINOR > 2
 +    .bdrv_probe_blocksizes          = vitastor_probe_blocksizes,
 +#endif