diff --git a/block.c b/block.c
index 45f653a88b..580cb77a70 100644
--- a/block.c
+++ b/block.c
@@ -84,6 +84,9 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
                                            BdrvChildRole child_role,
                                            Error **errp);
 
+static bool bdrv_recurse_has_child(BlockDriverState *bs,
+                                   BlockDriverState *child);
+
 static void bdrv_replace_child_noperm(BdrvChild *child,
                                       BlockDriverState *new_bs);
 static void bdrv_remove_file_or_backing_child(BlockDriverState *bs,
@@ -2673,6 +2676,7 @@ static void bdrv_replace_child_noperm(BdrvChild *child,
     int drain_saldo;
 
     assert(!child->frozen);
+    assert(old_bs != new_bs);
 
     if (old_bs && new_bs) {
         assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs));
@@ -2892,6 +2896,12 @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs,
 
     assert(parent_bs->drv);
 
+    if (bdrv_recurse_has_child(child_bs, parent_bs)) {
+        error_setg(errp, "Making '%s' a %s child of '%s' would create a cycle",
+                   child_bs->node_name, child_name, parent_bs->node_name);
+        return -EINVAL;
+    }
+
     bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm);
     bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL,
                     perm, shared_perm, &perm, &shared_perm);
diff --git a/block/block-backend.c b/block/block-backend.c
index 39cd99df2b..12ef80ea17 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1540,7 +1540,7 @@ BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
                             QEMUIOVector *qiov, BdrvRequestFlags flags,
                             BlockCompletionFunc *cb, void *opaque)
 {
-    assert(qiov->size <= INT64_MAX);
+    assert((uint64_t)qiov->size <= INT64_MAX);
     return blk_aio_prwv(blk, offset, qiov->size, qiov,
                         blk_aio_write_entry, flags, cb, opaque);
 }
diff --git a/block/export/fuse.c b/block/export/fuse.c
index 2e3bf8270b..823c126d23 100644
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -31,6 +31,10 @@
 #include <fuse.h>
 #include <fuse_lowlevel.h>
 
+#if defined(CONFIG_FALLOCATE_ZERO_RANGE)
+#include <linux/falloc.h>
+#endif
+
 #ifdef __linux__
 #include <linux/fs.h>
 #endif
diff --git a/block/file-posix.c b/block/file-posix.c
index 53be0bdc1b..7a27c83060 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -150,6 +150,8 @@ typedef struct BDRVRawState {
     uint64_t locked_perm;
     uint64_t locked_shared_perm;
 
+    uint64_t aio_max_batch;
+
     int perm_change_fd;
     int perm_change_flags;
     BDRVReopenState *reopen_state;
@@ -530,6 +532,11 @@ static QemuOptsList raw_runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "host AIO implementation (threads, native, io_uring)",
         },
+        {
+            .name = "aio-max-batch",
+            .type = QEMU_OPT_NUMBER,
+            .help = "AIO max batch size (0 = auto handled by AIO backend, default: 0)",
+        },
         {
             .name = "locking",
             .type = QEMU_OPT_STRING,
@@ -609,6 +616,8 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     s->use_linux_io_uring = (aio == BLOCKDEV_AIO_OPTIONS_IO_URING);
 #endif
 
+    s->aio_max_batch = qemu_opt_get_number(opts, "aio-max-batch", 0);
+
     locking = qapi_enum_parse(&OnOffAuto_lookup,
                               qemu_opt_get(opts, "locking"),
                               ON_OFF_AUTO_AUTO, &local_err);
@@ -1807,7 +1816,7 @@ static int handle_aiocb_copy_range(void *opaque)
 static int handle_aiocb_discard(void *opaque)
 {
     RawPosixAIOData *aiocb = opaque;
-    int ret = -EOPNOTSUPP;
+    int ret = -ENOTSUP;
     BDRVRawState *s = aiocb->bs->opaque;
 
     if (!s->has_discard) {
@@ -1829,7 +1838,7 @@ static int handle_aiocb_discard(void *opaque)
 #ifdef CONFIG_FALLOCATE_PUNCH_HOLE
         ret = do_fallocate(s->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
                            aiocb->aio_offset, aiocb->aio_nbytes);
-        ret = translate_err(-errno);
+        ret = translate_err(ret);
 #elif defined(__APPLE__) && (__MACH__)
         fpunchhole_t fpunchhole;
         fpunchhole.fp_flags = 0;
@@ -2057,7 +2066,8 @@ static int coroutine_fn raw_co_prw(BlockDriverState *bs, uint64_t offset,
     } else if (s->use_linux_aio) {
         LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
         assert(qiov->size == bytes);
-        return laio_co_submit(bs, aio, s->fd, offset, qiov, type);
+        return laio_co_submit(bs, aio, s->fd, offset, qiov, type,
+                              s->aio_max_batch);
 #endif
     }
 
@@ -2115,7 +2125,7 @@ static void raw_aio_unplug(BlockDriverState *bs)
 #ifdef CONFIG_LINUX_AIO
     if (s->use_linux_aio) {
         LinuxAioState *aio = aio_get_linux_aio(bdrv_get_aio_context(bs));
-        laio_io_unplug(bs, aio);
+        laio_io_unplug(bs, aio, s->aio_max_batch);
     }
 #endif
 #ifdef CONFIG_LINUX_IO_URING
diff --git a/block/linux-aio.c b/block/linux-aio.c
index 0dab507b71..f53ae72e21 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -334,30 +334,45 @@ static void ioq_submit(LinuxAioState *s)
     }
 }
 
+static uint64_t laio_max_batch(LinuxAioState *s, uint64_t dev_max_batch)
+{
+    uint64_t max_batch = s->aio_context->aio_max_batch ?: DEFAULT_MAX_BATCH;
+
+    /*
+     * AIO context can be shared between multiple block devices, so
+     * `dev_max_batch` allows reducing the batch size for latency-sensitive
+     * devices.
+     */
+    max_batch = MIN_NON_ZERO(dev_max_batch, max_batch);
+
+    /* limit the batch with the number of available events */
+    max_batch = MIN_NON_ZERO(MAX_EVENTS - s->io_q.in_flight, max_batch);
+
+    return max_batch;
+}
+
 void laio_io_plug(BlockDriverState *bs, LinuxAioState *s)
 {
     s->io_q.plugged++;
 }
 
-void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s)
+void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s,
+                    uint64_t dev_max_batch)
 {
     assert(s->io_q.plugged);
-    if (--s->io_q.plugged == 0 &&
-        !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
+    if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch) ||
+        (--s->io_q.plugged == 0 &&
+         !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending))) {
         ioq_submit(s);
     }
 }
 
 static int laio_do_submit(int fd, struct qemu_laiocb *laiocb, off_t offset,
-                          int type)
+                          int type, uint64_t dev_max_batch)
 {
     LinuxAioState *s = laiocb->ctx;
     struct iocb *iocbs = &laiocb->iocb;
     QEMUIOVector *qiov = laiocb->qiov;
-    int64_t max_batch = s->aio_context->aio_max_batch ?: DEFAULT_MAX_BATCH;
-
-    /* limit the batch with the number of available events */
-    max_batch = MIN_NON_ZERO(MAX_EVENTS - s->io_q.in_flight, max_batch);
 
     switch (type) {
     case QEMU_AIO_WRITE:
@@ -378,7 +393,7 @@ static int laio_do_submit(int fd, struct qemu_laiocb *laiocb, off_t offset,
     s->io_q.in_queue++;
     if (!s->io_q.blocked &&
         (!s->io_q.plugged ||
-         s->io_q.in_queue >= max_batch)) {
+         s->io_q.in_queue >= laio_max_batch(s, dev_max_batch))) {
         ioq_submit(s);
     }
 
@@ -386,7 +401,8 @@ static int laio_do_submit(int fd, struct qemu_laiocb *laiocb, off_t offset,
 }
 
 int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
-                                uint64_t offset, QEMUIOVector *qiov, int type)
+                                uint64_t offset, QEMUIOVector *qiov, int type,
+                                uint64_t dev_max_batch)
 {
     int ret;
     struct qemu_laiocb laiocb = {
@@ -398,7 +414,7 @@ int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
         .qiov       = qiov,
     };
 
-    ret = laio_do_submit(fd, &laiocb, offset, type);
+    ret = laio_do_submit(fd, &laiocb, offset, type, dev_max_batch);
     if (ret < 0) {
         return ret;
     }
diff --git a/block/nvme.c b/block/nvme.c
index 1cc7b62bb4..e4f336d79c 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -183,15 +183,20 @@ static bool nvme_init_queue(BDRVNVMeState *s, NVMeQueue *q,
     return r == 0;
 }
 
+static void nvme_free_queue(NVMeQueue *q)
+{
+    qemu_vfree(q->queue);
+}
+
 static void nvme_free_queue_pair(NVMeQueuePair *q)
 {
-    trace_nvme_free_queue_pair(q->index, q);
+    trace_nvme_free_queue_pair(q->index, q, &q->cq, &q->sq);
     if (q->completion_bh) {
         qemu_bh_delete(q->completion_bh);
     }
+    nvme_free_queue(&q->sq);
+    nvme_free_queue(&q->cq);
     qemu_vfree(q->prp_list_pages);
-    qemu_vfree(q->sq.queue);
-    qemu_vfree(q->cq.queue);
     qemu_mutex_destroy(&q->lock);
     g_free(q);
 }
@@ -514,10 +519,10 @@ static bool nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
 {
     BDRVNVMeState *s = bs->opaque;
     bool ret = false;
-    union {
+    QEMU_AUTO_VFREE union {
         NvmeIdCtrl ctrl;
         NvmeIdNs ns;
-    } *id;
+    } *id = NULL;
     NvmeLBAF *lbaf;
     uint16_t oncs;
     int r;
@@ -595,7 +600,6 @@ static bool nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
     s->blkshift = lbaf->ds;
 out:
     qemu_vfio_dma_unmap(s->vfio, id);
-    qemu_vfree(id);
 
     return ret;
 }
@@ -1219,7 +1223,7 @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 {
     BDRVNVMeState *s = bs->opaque;
     int r;
-    uint8_t *buf = NULL;
+    QEMU_AUTO_VFREE uint8_t *buf = NULL;
     QEMUIOVector local_qiov;
     size_t len = QEMU_ALIGN_UP(bytes, qemu_real_host_page_size);
     assert(QEMU_IS_ALIGNED(offset, s->page_size));
@@ -1246,7 +1250,6 @@ static int nvme_co_prw(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     if (!r && !is_write) {
         qemu_iovec_from_buf(qiov, 0, buf, bytes);
     }
-    qemu_vfree(buf);
     return r;
 }
 
@@ -1365,7 +1368,7 @@ static int coroutine_fn nvme_co_pdiscard(BlockDriverState *bs,
     BDRVNVMeState *s = bs->opaque;
     NVMeQueuePair *ioq = s->queues[INDEX_IO(0)];
     NVMeRequest *req;
-    NvmeDsmRange *buf;
+    QEMU_AUTO_VFREE NvmeDsmRange *buf = NULL;
     QEMUIOVector local_qiov;
     int ret;
 
@@ -1440,7 +1443,6 @@ static int coroutine_fn nvme_co_pdiscard(BlockDriverState *bs,
     trace_nvme_dsm_done(s, offset, bytes, ret);
 out:
     qemu_iovec_destroy(&local_qiov);
-    qemu_vfree(buf);
     return ret;
 
 }
diff --git a/block/rbd.c b/block/rbd.c
index 701fbf2b0c..def96292e0 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -97,6 +97,12 @@ typedef struct RBDTask {
     int64_t ret;
 } RBDTask;
 
+typedef struct RBDDiffIterateReq {
+    uint64_t offs;
+    uint64_t bytes;
+    bool exists;
+} RBDDiffIterateReq;
+
 static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
                             BlockdevOptionsRbd *opts, bool cache,
                             const char *keypairs, const char *secretid,
@@ -1259,6 +1265,111 @@ static ImageInfoSpecific *qemu_rbd_get_specific_info(BlockDriverState *bs,
     return spec_info;
 }
 
+/*
+ * rbd_diff_iterate2 allows to interrupt the exection by returning a negative
+ * value in the callback routine. Choose a value that does not conflict with
+ * an existing exitcode and return it if we want to prematurely stop the
+ * execution because we detected a change in the allocation status.
+ */
+#define QEMU_RBD_EXIT_DIFF_ITERATE2 -9000
+
+static int qemu_rbd_diff_iterate_cb(uint64_t offs, size_t len,
+                                    int exists, void *opaque)
+{
+    RBDDiffIterateReq *req = opaque;
+
+    assert(req->offs + req->bytes <= offs);
+    /*
+     * we do not diff against a snapshot so we should never receive a callback
+     * for a hole.
+     */
+    assert(exists);
+
+    if (!req->exists && offs > req->offs) {
+        /*
+         * we started in an unallocated area and hit the first allocated
+         * block. req->bytes must be set to the length of the unallocated area
+         * before the allocated area. stop further processing.
+         */
+        req->bytes = offs - req->offs;
+        return QEMU_RBD_EXIT_DIFF_ITERATE2;
+    }
+
+    if (req->exists && offs > req->offs + req->bytes) {
+        /*
+         * we started in an allocated area and jumped over an unallocated area,
+         * req->bytes contains the length of the allocated area before the
+         * unallocated area. stop further processing.
+         */
+        return QEMU_RBD_EXIT_DIFF_ITERATE2;
+    }
+
+    req->bytes += len;
+    req->exists = true;
+
+    return 0;
+}
+
+static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,
+                                                 bool want_zero, int64_t offset,
+                                                 int64_t bytes, int64_t *pnum,
+                                                 int64_t *map,
+                                                 BlockDriverState **file)
+{
+    BDRVRBDState *s = bs->opaque;
+    int status, r;
+    RBDDiffIterateReq req = { .offs = offset };
+    uint64_t features, flags;
+
+    assert(offset + bytes <= s->image_size);
+
+    /* default to all sectors allocated */
+    status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
+    *map = offset;
+    *file = bs;
+    *pnum = bytes;
+
+    /* check if RBD image supports fast-diff */
+    r = rbd_get_features(s->image, &features);
+    if (r < 0) {
+        return status;
+    }
+    if (!(features & RBD_FEATURE_FAST_DIFF)) {
+        return status;
+    }
+
+    /* check if RBD fast-diff result is valid */
+    r = rbd_get_flags(s->image, &flags);
+    if (r < 0) {
+        return status;
+    }
+    if (flags & RBD_FLAG_FAST_DIFF_INVALID) {
+        return status;
+    }
+
+    r = rbd_diff_iterate2(s->image, NULL, offset, bytes, true, true,
+                          qemu_rbd_diff_iterate_cb, &req);
+    if (r < 0 && r != QEMU_RBD_EXIT_DIFF_ITERATE2) {
+        return status;
+    }
+    assert(req.bytes <= bytes);
+    if (!req.exists) {
+        if (r == 0) {
+            /*
+             * rbd_diff_iterate2 does not invoke callbacks for unallocated
+             * areas. This here catches the case where no callback was
+             * invoked at all (req.bytes == 0).
+             */
+            assert(req.bytes == 0);
+            req.bytes = bytes;
+        }
+        status = BDRV_BLOCK_ZERO | BDRV_BLOCK_OFFSET_VALID;
+    }
+
+    *pnum = req.bytes;
+    return status;
+}
+
 static int64_t qemu_rbd_getlength(BlockDriverState *bs)
 {
     BDRVRBDState *s = bs->opaque;
@@ -1494,6 +1605,7 @@ static BlockDriver bdrv_rbd = {
 #ifdef LIBRBD_SUPPORTS_WRITE_ZEROES
     .bdrv_co_pwrite_zeroes  = qemu_rbd_co_pwrite_zeroes,
 #endif
+    .bdrv_co_block_status   = qemu_rbd_co_block_status,
 
     .bdrv_snapshot_create   = qemu_rbd_snap_create,
     .bdrv_snapshot_delete   = qemu_rbd_snap_remove,
diff --git a/block/trace-events b/block/trace-events
index ab56edacb4..549090d453 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -157,7 +157,7 @@ nvme_dsm_done(void *s, int64_t offset, int64_t bytes, int ret) "s %p offset 0x%"
 nvme_dma_map_flush(void *s) "s %p"
 nvme_free_req_queue_wait(void *s, unsigned q_index) "s %p q #%u"
 nvme_create_queue_pair(unsigned q_index, void *q, size_t size, void *aio_context, int fd) "index %u q %p size %zu aioctx %p fd %d"
-nvme_free_queue_pair(unsigned q_index, void *q) "index %u q %p"
+nvme_free_queue_pair(unsigned q_index, void *q, void *cq, void *sq) "index %u q %p cq %p sq %p"
 nvme_cmd_map_qiov(void *s, void *cmd, void *req, void *qiov, int entries) "s %p cmd %p req %p qiov %p entries %d"
 nvme_cmd_map_qiov_pages(void *s, int i, uint64_t page) "s %p page[%d] 0x%"PRIx64
 nvme_cmd_map_qiov_iov(void *s, int i, void *page, int pages) "s %p iov[%d] %p pages %d"
diff --git a/hw/ide/core.c b/hw/ide/core.c
index fd69ca3167..e28f8aad61 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -98,8 +98,12 @@ static void put_le16(uint16_t *p, unsigned int v)
 static void ide_identify_size(IDEState *s)
 {
     uint16_t *p = (uint16_t *)s->identify_data;
-    put_le16(p + 60, s->nb_sectors);
-    put_le16(p + 61, s->nb_sectors >> 16);
+    int64_t nb_sectors_lba28 = s->nb_sectors;
+    if (nb_sectors_lba28 >= 1 << 28) {
+        nb_sectors_lba28 = (1 << 28) - 1;
+    }
+    put_le16(p + 60, nb_sectors_lba28);
+    put_le16(p + 61, nb_sectors_lba28 >> 16);
     put_le16(p + 100, s->nb_sectors);
     put_le16(p + 101, s->nb_sectors >> 16);
     put_le16(p + 102, s->nb_sectors >> 32);
diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h
index 251b10d273..21fc10c4c9 100644
--- a/include/block/raw-aio.h
+++ b/include/block/raw-aio.h
@@ -51,11 +51,13 @@ typedef struct LinuxAioState LinuxAioState;
 LinuxAioState *laio_init(Error **errp);
 void laio_cleanup(LinuxAioState *s);
 int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
-                                uint64_t offset, QEMUIOVector *qiov, int type);
+                                uint64_t offset, QEMUIOVector *qiov, int type,
+                                uint64_t dev_max_batch);
 void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context);
 void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context);
 void laio_io_plug(BlockDriverState *bs, LinuxAioState *s);
-void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s);
+void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s,
+                    uint64_t dev_max_batch);
 #endif
 /* io_uring.c - Linux io_uring implementation */
 #ifdef CONFIG_LINUX_IO_URING
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 69698a4ffe..b290782bf2 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2939,6 +2939,12 @@
 #              for this device (default: none, forward the commands via SG_IO;
 #              since 2.11)
 # @aio: AIO backend (default: threads) (since: 2.8)
+# @aio-max-batch: maximum number of requests to batch together into a single
+#                 submission in the AIO backend. The smallest value between
+#                 this and the aio-max-batch value of the IOThread object is
+#                 chosen.
+#                 0 means that the AIO backend will handle it automatically.
+#                 (default: 0, since 6.2)
 # @locking: whether to enable file locking. If set to 'auto', only enable
 #           when Open File Descriptor (OFD) locking API is available
 #           (default: auto, since 2.10)
@@ -2968,6 +2974,7 @@
             '*pr-manager': 'str',
             '*locking': 'OnOffAuto',
             '*aio': 'BlockdevAioOptions',
+            '*aio-max-batch': 'int',
             '*drop-cache': {'type': 'bool',
                             'if': 'CONFIG_LINUX'},
             '*x-check-cache-dropped': { 'type': 'bool',
diff --git a/tests/qemu-iotests/085 b/tests/qemu-iotests/085
index d557522943..de74262a26 100755
--- a/tests/qemu-iotests/085
+++ b/tests/qemu-iotests/085
@@ -103,11 +103,18 @@ do_blockdev_add()
 }
 
 # ${1}: unique identifier for the snapshot filename
-add_snapshot_image()
+create_snapshot_image()
 {
     base_image="${TEST_DIR}/$((${1}-1))-${snapshot_virt0}"
     snapshot_file="${TEST_DIR}/${1}-${snapshot_virt0}"
     TEST_IMG=$snapshot_file _make_test_img -u -b "${base_image}" -F $IMGFMT "$size"
+}
+
+# ${1}: unique identifier for the snapshot filename
+add_snapshot_image()
+{
+    snapshot_file="${TEST_DIR}/${1}-${snapshot_virt0}"
+    create_snapshot_image "$1"
     do_blockdev_add "$1" "'backing': null, " "${snapshot_file}"
 }
 
@@ -230,6 +237,28 @@ _make_test_img -b "${TEST_IMG}.base" -F $IMGFMT "$size"
 do_blockdev_add ${SNAPSHOTS} "" "${TEST_IMG}"
 blockdev_snapshot ${SNAPSHOTS} error
 
+echo
+echo === Invalid command - creating loops ===
+echo
+
+SNAPSHOTS=$((${SNAPSHOTS}+1))
+add_snapshot_image ${SNAPSHOTS}
+
+_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
+                     'arguments': { 'node':'snap_${SNAPSHOTS}',
+                                    'overlay':'snap_${SNAPSHOTS}' }
+                   }" "error"
+
+SNAPSHOTS=$((${SNAPSHOTS}+1))
+create_snapshot_image ${SNAPSHOTS}
+do_blockdev_add ${SNAPSHOTS} "'backing': 'snap_$((${SNAPSHOTS}-1))', " \
+    "${TEST_DIR}/${SNAPSHOTS}-${snapshot_virt0}"
+
+_send_qemu_cmd $h "{ 'execute': 'blockdev-snapshot',
+                     'arguments': { 'node':'snap_${SNAPSHOTS}',
+                                    'overlay':'snap_$((${SNAPSHOTS}-1))' }
+                   }" "error"
+
 echo
 echo === Invalid command - The node does not exist ===
 echo
diff --git a/tests/qemu-iotests/085.out b/tests/qemu-iotests/085.out
index 1d4c565b6d..b543b992ff 100644
--- a/tests/qemu-iotests/085.out
+++ b/tests/qemu-iotests/085.out
@@ -217,15 +217,42 @@ Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/
                                      'overlay':'snap_13' } }
 {"error": {"class": "GenericError", "desc": "The overlay already has a backing image"}}
 
+=== Invalid command - creating loops ===
+
+Formatting 'TEST_DIR/14-snapshot-v0.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/13-snapshot-v0.IMGFMT backing_fmt=IMGFMT
+{ 'execute': 'blockdev-add', 'arguments':
+           { 'driver': 'IMGFMT', 'node-name': 'snap_14', 'backing': null,
+             'file':
+             { 'driver': 'file', 'filename': 'TEST_DIR/14-snapshot-v0.IMGFMT',
+               'node-name': 'file_14' } } }
+{"return": {}}
+{ 'execute': 'blockdev-snapshot',
+                     'arguments': { 'node':'snap_14',
+                                    'overlay':'snap_14' }
+                   }
+{"error": {"class": "GenericError", "desc": "Making 'snap_14' a backing child of 'snap_14' would create a cycle"}}
+Formatting 'TEST_DIR/15-snapshot-v0.IMGFMT', fmt=IMGFMT size=134217728 backing_file=TEST_DIR/14-snapshot-v0.IMGFMT backing_fmt=IMGFMT
+{ 'execute': 'blockdev-add', 'arguments':
+           { 'driver': 'IMGFMT', 'node-name': 'snap_15', 'backing': 'snap_14',
+             'file':
+             { 'driver': 'file', 'filename': 'TEST_DIR/15-snapshot-v0.IMGFMT',
+               'node-name': 'file_15' } } }
+{"return": {}}
+{ 'execute': 'blockdev-snapshot',
+                     'arguments': { 'node':'snap_15',
+                                    'overlay':'snap_14' }
+                   }
+{"error": {"class": "GenericError", "desc": "Making 'snap_15' a backing child of 'snap_14' would create a cycle"}}
+
 === Invalid command - The node does not exist ===
 
 { 'execute': 'blockdev-snapshot',
                       'arguments': { 'node': 'virtio0',
-                                     'overlay':'snap_14' } }
-{"error": {"class": "GenericError", "desc": "Cannot find device='snap_14' nor node-name='snap_14'"}}
+                                     'overlay':'snap_16' } }
+{"error": {"class": "GenericError", "desc": "Cannot find device='snap_16' nor node-name='snap_16'"}}
 { 'execute': 'blockdev-snapshot',
                      'arguments': { 'node':'nodevice',
-                                    'overlay':'snap_13' }
+                                    'overlay':'snap_15' }
                    }
 {"error": {"class": "GenericError", "desc": "Cannot find device='nodevice' nor node-name='nodevice'"}}
 *** done