diff --git a/blockstore.cpp b/blockstore.cpp
index 32ed4a48..78a4a7bb 100644
--- a/blockstore.cpp
+++ b/blockstore.cpp
@@ -59,6 +59,11 @@ blockstore::~blockstore()
     free(journal.sector_info);
 }
 
+bool blockstore::is_started()
+{
+    return initialized == 10;
+}
+
 // main event loop - produce requests
 void blockstore::loop()
 {
diff --git a/blockstore.h b/blockstore.h
index 30615bdf..ef130671 100644
--- a/blockstore.h
+++ b/blockstore.h
@@ -211,7 +211,7 @@ struct blockstore_operation
     uint32_t offset;
     // For stabilize requests: buf contains <len> obj_ver_id's to stabilize
     uint32_t len;
-    uint8_t *buf;
+    uint8_t *buf; // FIXME: void*
     int retval;
 
     // FIXME: Move internal fields somewhere
@@ -325,6 +325,8 @@ public:
     // Event loop
     void loop();
 
+    bool is_started();
+
     // Returns true when it's safe to destroy the instance. If destroying the instance
     // requires to purge some queues, starts that process. Should be called in the event
     // loop until it returns true.
diff --git a/blockstore_write.cpp b/blockstore_write.cpp
index c1a57891..4ccaaff9 100644
--- a/blockstore_write.cpp
+++ b/blockstore_write.cpp
@@ -3,16 +3,21 @@
 void blockstore::enqueue_write(blockstore_operation *op)
 {
     // Assign version number
-    auto dirty_it = dirty_db.upper_bound((obj_ver_id){
-        .oid = op->oid,
-        .version = UINT64_MAX,
-    });
-    dirty_it--;
-    if (dirty_it != dirty_db.end() && dirty_it->first.oid == op->oid)
+    bool found = false;
+    if (dirty_db.size() > 0)
     {
-        op->version = dirty_it->first.version + 1;
+        auto dirty_it = dirty_db.upper_bound((obj_ver_id){
+            .oid = op->oid,
+            .version = UINT64_MAX,
+        });
+        dirty_it--;
+        if (dirty_it != dirty_db.end() && dirty_it->first.oid == op->oid)
+        {
+            found = true;
+            op->version = dirty_it->first.version + 1;
+        }
     }
-    else
+    if (!found)
     {
         auto clean_it = clean_db.find(op->oid);
         if (clean_it != clean_db.end())
diff --git a/test.cpp b/test.cpp
index 5e23221a..bcc5fe41 100644
--- a/test.cpp
+++ b/test.cpp
@@ -212,10 +212,11 @@ int main(int argc, char *argv[])
 {
     std::map<int, std::string> strs;
     strs.emplace(12, "str");
-    auto it = strs.upper_bound(11);
-    printf("s = %d %s %d\n", it->first, it->second.c_str(), it == strs.begin());
+    auto it = strs.upper_bound(13);
+    //printf("s = %d %s %d\n", it->first, it->second.c_str(), it == strs.begin());
     it--;
-    printf("s = %d %s\n", it->first, it->second.c_str());
+    printf("%d\n", it == strs.end());
+    //printf("s = %d %s\n", it->first, it->second.c_str());
     struct io_uring ring;
     int fd = open("/dev/loop0", O_RDWR | O_DIRECT, 0644);
     if (fd < 0)
diff --git a/test_blockstore.cpp b/test_blockstore.cpp
index 6ad09233..27bdd176 100644
--- a/test_blockstore.cpp
+++ b/test_blockstore.cpp
@@ -10,8 +10,9 @@ class timerfd_interval
     int status;
     ring_loop_t *ringloop;
     ring_consumer_t consumer;
+    std::function<void(void)> callback;
 public:
-    timerfd_interval(ring_loop_t *ringloop, int seconds)
+    timerfd_interval(ring_loop_t *ringloop, int seconds, std::function<void(void)> cb)
     {
         wait_state = 0;
         timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
@@ -30,6 +31,7 @@ public:
         consumer.loop = [this]() { loop(); };
         ringloop->register_consumer(consumer);
         this->ringloop = ringloop;
+        this->callback = cb;
     }
 
     ~timerfd_interval()
@@ -61,7 +63,7 @@ public:
             uint64_t n;
             read(timerfd, &n, 8);
             wait_state = 0;
-            printf("tick 1s\n");
+            callback();
         };
         wait_state = 1;
         ringloop->submit();
@@ -76,13 +78,33 @@ int main(int narg, char *args[])
     config["data_device"] = "./test_data.bin";
     ring_loop_t *ringloop = new ring_loop_t(512);
     blockstore *bs = new blockstore(config, ringloop);
-    // print "tick" every second
-    timerfd_interval tick_tfd(ringloop, 1);
+    timerfd_interval tick_tfd(ringloop, 1, []()
+    {
+        printf("tick 1s\n");
+    });
+    blockstore_operation op;
+    op.flags = OP_WRITE;
+    op.oid = { .inode = 1, .stripe = 0 };
+    op.version = 0;
+    op.offset = 4096;
+    op.len = 4096;
+    op.buf = (uint8_t*)memalign(512, 4096);
+    memset(op.buf, 0xaa, 4096);
+    op.callback = [](blockstore_operation *op)
+    {
+        printf("completed %d\n", op->retval);
+    };
+    bool bs_was_done = false;
     while (true)
     {
+        bool bs_done = bs->is_started();
+        if (bs_done && !bs_was_done)
+        {
+            bs->enqueue_op(&op);
+            bs_was_done = true;
+        }
         ringloop->loop(true);
     }
-    
     delete bs;
     delete ringloop;
     return 0;