diff --git a/lib/blob/blobstore.c b/lib/blob/blobstore.c
index 943e2e9cd..1b77bcfe3 100644
--- a/lib/blob/blobstore.c
+++ b/lib/blob/blobstore.c
@@ -50,6 +50,8 @@
 static int spdk_bs_register_md_thread(struct spdk_blob_store *bs);
 static int spdk_bs_unregister_md_thread(struct spdk_blob_store *bs);
 static void _spdk_blob_close_cpl(spdk_bs_sequence_t *seq, void *cb_arg, int bserrno);
+void _spdk_blob_insert_cluster_on_md_thread(struct spdk_blob_data *blob, uint32_t cluster_num,
+		uint64_t cluster, spdk_blob_op_complete cb_fn, void *cb_arg);
 
 static inline size_t
 divide_round_up(size_t num, size_t divisor)
@@ -3214,6 +3216,71 @@ spdk_blob_sync_md(struct spdk_blob *_blob, spdk_blob_op_complete cb_fn, void *cb
 
 /* END spdk_blob_sync_md */
 
+struct spdk_blob_insert_cluster_ctx {
+	struct spdk_thread	*thread;
+	struct spdk_blob_data	*blob;
+	uint32_t		cluster_num;	/* cluster index in blob */
+	uint32_t		cluster;	/* cluster on disk */
+	int			rc;
+	spdk_blob_op_complete	cb_fn;
+	void			*cb_arg;
+};
+
+static void
+_spdk_blob_insert_cluster_msg_cpl(void *arg)
+{
+	struct spdk_blob_insert_cluster_ctx *ctx = arg;
+
+	ctx->cb_fn(ctx->cb_arg, ctx->rc);
+	free(ctx);
+}
+
+static void
+_spdk_blob_insert_cluster_msg_cb(void *arg, int bserrno)
+{
+	struct spdk_blob_insert_cluster_ctx *ctx = arg;
+
+	ctx->rc = bserrno;
+	spdk_thread_send_msg(ctx->thread, _spdk_blob_insert_cluster_msg_cpl, ctx);
+}
+
+static void
+_spdk_blob_insert_cluster_msg(void *arg)
+{
+	struct spdk_blob_insert_cluster_ctx *ctx = arg;
+
+	ctx->rc = _spdk_blob_insert_cluster(ctx->blob, ctx->cluster_num, ctx->cluster);
+	if (ctx->rc != 0) {
+		spdk_thread_send_msg(ctx->thread, _spdk_blob_insert_cluster_msg_cpl, ctx);
+		return;
+	}
+
+	ctx->blob->state = SPDK_BLOB_STATE_DIRTY;
+	_spdk_blob_sync_md(ctx->blob, _spdk_blob_insert_cluster_msg_cb, ctx);
+}
+
+void
+_spdk_blob_insert_cluster_on_md_thread(struct spdk_blob_data *blob, uint32_t cluster_num,
+				       uint64_t cluster, spdk_blob_op_complete cb_fn, void *cb_arg)
+{
+	struct spdk_blob_insert_cluster_ctx *ctx;
+
+	ctx = calloc(1, sizeof(*ctx));
+	if (ctx == NULL) {
+		cb_fn(cb_arg, -ENOMEM);
+		return;
+	}
+
+	ctx->thread = spdk_get_thread();
+	ctx->blob = blob;
+	ctx->cluster_num = cluster_num;
+	ctx->cluster = cluster;
+	ctx->cb_fn = cb_fn;
+	ctx->cb_arg = cb_arg;
+
+	spdk_thread_send_msg(blob->bs->md_thread, _spdk_blob_insert_cluster_msg, ctx);
+}
+
 /* START spdk_blob_close */
 
 static void
diff --git a/test/unit/lib/blob/blob.c/blob_ut.c b/test/unit/lib/blob/blob.c/blob_ut.c
index 75b824283..f052b0a95 100644
--- a/test/unit/lib/blob/blob.c/blob_ut.c
+++ b/test/unit/lib/blob/blob.c/blob_ut.c
@@ -2679,7 +2679,7 @@ blob_thin_prov_alloc(void)
 
 	spdk_bs_open_blob(g_bs, blobid, blob_op_with_handle_complete, NULL);
 	CU_ASSERT(g_bserrno == 0);
-	CU_ASSERT(g_blob != NULL);
+	SPDK_CU_ASSERT_FATAL(g_blob != NULL);
 	blob = g_blob;
 	blob_data = __blob_to_data(blob);
 
@@ -2698,6 +2698,88 @@ blob_thin_prov_alloc(void)
 	g_bs = NULL;
 }
 
+static void
+blob_insert_cluster_msg(void)
+{
+	struct spdk_blob_store *bs;
+	struct spdk_bs_dev *dev;
+	struct spdk_blob *blob;
+	struct spdk_blob_data *blob_data;
+	struct spdk_blob_opts opts;
+	spdk_blob_id blobid;
+	uint64_t free_clusters;
+
+	dev = init_dev();
+
+	spdk_bs_init(dev, NULL, bs_op_with_handle_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	SPDK_CU_ASSERT_FATAL(g_bs != NULL);
+	bs = g_bs;
+	free_clusters = spdk_bs_free_cluster_count(bs);
+
+	/* Set blob as thin provisioned */
+	spdk_blob_opts_init(&opts);
+	opts.thin_provision = true;
+	opts.num_clusters = 4;
+
+	spdk_bs_create_blob_ext(bs, &opts, blob_op_with_id_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	CU_ASSERT(g_blobid != SPDK_BLOBID_INVALID);
+	CU_ASSERT(free_clusters == spdk_bs_free_cluster_count(bs));
+	blobid = g_blobid;
+
+	spdk_bs_open_blob(bs, blobid, blob_op_with_handle_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	SPDK_CU_ASSERT_FATAL(g_blob != NULL);
+	blob = g_blob;
+	blob_data = __blob_to_data(blob);
+
+	CU_ASSERT(blob_data->active.num_clusters == 4);
+	CU_ASSERT(spdk_blob_get_num_clusters(blob) == 4);
+	CU_ASSERT(blob_data->active.clusters[1] == 0);
+
+	_spdk_bs_claim_cluster(bs, 0xF);
+	_spdk_blob_insert_cluster_on_md_thread(blob_data, 1, 0xF, blob_op_complete, NULL);
+
+	CU_ASSERT(blob_data->active.clusters[1] != 0);
+
+	spdk_blob_close(blob, blob_op_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+
+	/* Unload the blob store */
+	spdk_bs_unload(g_bs, bs_op_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	g_bs = NULL;
+	g_blob = NULL;
+	g_blobid = 0;
+
+	/* Load an existing blob store */
+	dev = init_dev();
+	spdk_bs_load(dev, NULL, bs_op_with_handle_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	SPDK_CU_ASSERT_FATAL(g_bs != NULL);
+
+	bs = g_bs;
+
+	spdk_bs_open_blob(g_bs, blobid, blob_op_with_handle_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	CU_ASSERT(g_blob != NULL);
+	blob = g_blob;
+	blob_data = __blob_to_data(blob);
+
+	CU_ASSERT(blob_data->active.clusters[1] != 0);
+
+	spdk_blob_close(blob, blob_op_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+
+	spdk_bs_delete_blob(bs, blobid, blob_op_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+
+	spdk_bs_unload(g_bs, bs_op_complete, NULL);
+	CU_ASSERT(g_bserrno == 0);
+	g_bs = NULL;
+}
+
 int main(int argc, char **argv)
 {
 	CU_pSuite	suite = NULL;
@@ -2746,7 +2828,8 @@ int main(int argc, char **argv)
 		CU_add_test(suite, "blob_flags", blob_flags) == NULL ||
 		CU_add_test(suite, "bs_version", bs_version) == NULL ||
 		CU_add_test(suite, "blob_set_xattrs", blob_set_xattrs) == NULL ||
-		CU_add_test(suite, "blob_thin_prov_alloc", blob_thin_prov_alloc) == NULL
+		CU_add_test(suite, "blob_thin_prov_alloc", blob_thin_prov_alloc) == NULL ||
+		CU_add_test(suite, "blob_insert_cluster_msg", blob_insert_cluster_msg) == NULL
 	) {
 		CU_cleanup_registry();
 		return CU_get_error();