diff --git a/src/blockstore_impl.cpp b/src/blockstore_impl.cpp
index 390fa119..c2bcb5b3 100644
--- a/src/blockstore_impl.cpp
+++ b/src/blockstore_impl.cpp
@@ -101,21 +101,10 @@ void blockstore_impl_t::loop()
     {
         // try to submit ops
         unsigned initial_ring_space = ringloop->space_left();
-        // FIXME: rework this "sync polling"
-        auto cur_sync = in_progress_syncs.begin();
-        while (cur_sync != in_progress_syncs.end())
-        {
-            if (continue_sync(*cur_sync) != 2)
-            {
-                // List is unmodified
-                cur_sync++;
-            }
-            else
-            {
-                cur_sync = in_progress_syncs.begin();
-            }
-        }
         auto cur = submit_queue.begin();
+        // has_writes == 0 - no writes before the current queue item
+        // has_writes == 1 - some writes in progress
+        // has_writes == 2 - tried to submit some writes, but failed
         int has_writes = 0;
         while (cur != submit_queue.end())
         {
@@ -142,10 +131,12 @@ void blockstore_impl_t::loop()
             }
             unsigned ring_space = ringloop->space_left();
             unsigned prev_sqe_pos = ringloop->save();
-            bool dequeue_op = false;
+            bool dequeue_op = false, cancel_op = false;
+            bool has_in_progress_sync = false;
             if (op->opcode == BS_OP_READ)
             {
                 dequeue_op = dequeue_read(op);
+                cancel_op = !dequeue_op;
             }
             else if (op->opcode == BS_OP_WRITE || op->opcode == BS_OP_WRITE_STABLE)
             {
@@ -154,8 +145,13 @@ void blockstore_impl_t::loop()
                     // Some writes already could not be submitted
                     continue;
                 }
-                dequeue_op = dequeue_write(op);
-                has_writes = dequeue_op ? 1 : 2;
+                int wr_st = dequeue_write(op);
+                // 0 = can't submit
+                // 1 = in progress
+                // 2 = completed, remove from queue
+                dequeue_op = wr_st == 2;
+                cancel_op = wr_st == 0;
+                has_writes = wr_st > 0 ? 1 : 2;
             }
             else if (op->opcode == BS_OP_DELETE)
             {
@@ -164,8 +160,10 @@ void blockstore_impl_t::loop()
                     // Some writes already could not be submitted
                     continue;
                 }
-                dequeue_op = dequeue_del(op);
-                has_writes = dequeue_op ? 1 : 2;
+                int wr_st = dequeue_del(op);
+                dequeue_op = wr_st == 2;
+                cancel_op = wr_st == 0;
+                has_writes = wr_st > 0 ? 1 : 2;
             }
             else if (op->opcode == BS_OP_SYNC)
             {
@@ -178,29 +176,39 @@ void blockstore_impl_t::loop()
                     // Can't submit SYNC before previous writes
                     continue;
                 }
-                dequeue_op = dequeue_sync(op);
+                int wr_st = continue_sync(op, has_in_progress_sync);
+                dequeue_op = wr_st == 2;
+                cancel_op = wr_st == 0;
+                if (dequeue_op != 2)
+                {
+                    // Or we could just set has_writes=1...
+                    has_in_progress_sync = true;
+                }
             }
             else if (op->opcode == BS_OP_STABLE)
             {
-                dequeue_op = dequeue_stable(op);
+                int wr_st = dequeue_stable(op);
+                dequeue_op = wr_st == 2;
+                cancel_op = wr_st == 0;
             }
             else if (op->opcode == BS_OP_ROLLBACK)
             {
-                dequeue_op = dequeue_rollback(op);
+                int wr_st = dequeue_rollback(op);
+                dequeue_op = wr_st == 2;
+                cancel_op = wr_st == 0;
             }
             else if (op->opcode == BS_OP_LIST)
             {
-                // LIST doesn't need to be blocked by previous modifications,
-                // it only needs to include all in-progress writes as they're guaranteed
-                // to be readable and stabilizable/rollbackable by subsequent operations
+                // LIST doesn't need to be blocked by previous modifications
                 process_list(op);
                 dequeue_op = true;
+                cancel_op = false;
             }
             if (dequeue_op)
             {
                 submit_queue.erase(op_ptr);
             }
-            else
+            if (cancel_op)
             {
                 ringloop->restore(prev_sqe_pos);
                 if (PRIV(op)->wait_for == WAIT_SQE)
@@ -233,7 +241,7 @@ bool blockstore_impl_t::is_safe_to_stop()
 {
     // It's safe to stop blockstore when there are no in-flight operations,
     // no in-progress syncs and flusher isn't doing anything
-    if (submit_queue.size() > 0 || in_progress_syncs.size() > 0 || !readonly && flusher->is_active())
+    if (submit_queue.size() > 0 || !readonly && flusher->is_active())
     {
         return false;
     }
@@ -374,12 +382,6 @@ void blockstore_impl_t::enqueue_op(blockstore_op_t *op, bool first)
         std::function<void (blockstore_op_t*)>(op->callback)(op);
         return;
     }
-    if (op->opcode == BS_OP_SYNC && immediate_commit == IMMEDIATE_ALL)
-    {
-        op->retval = 0;
-        std::function<void (blockstore_op_t*)>(op->callback)(op);
-        return;
-    }
     // Call constructor without allocating memory. We'll call destructor before returning op back
     new ((void*)op->private_data) blockstore_op_private_t;
     PRIV(op)->wait_for = 0;
diff --git a/src/blockstore_impl.h b/src/blockstore_impl.h
index 94636b12..f589c3ba 100644
--- a/src/blockstore_impl.h
+++ b/src/blockstore_impl.h
@@ -160,8 +160,6 @@ struct blockstore_op_private_t
     // Sync
     std::vector<obj_ver_id> sync_big_writes, sync_small_writes;
     int sync_small_checked, sync_big_checked;
-    std::list<blockstore_op_t*>::iterator in_progress_ptr;
-    int prev_sync_count;
 };
 
 // https://github.com/algorithm-ninja/cpp-btree
@@ -212,7 +210,6 @@ class blockstore_impl_t
     blockstore_dirty_db_t dirty_db;
     std::list<blockstore_op_t*> submit_queue; // FIXME: funny thing is that vector is better here
     std::vector<obj_ver_id> unsynced_big_writes, unsynced_small_writes;
-    std::list<blockstore_op_t*> in_progress_syncs; // ...and probably here, too
     allocator *data_alloc = NULL;
     uint8_t *zero_object;
 
@@ -279,11 +276,9 @@ class blockstore_impl_t
     void handle_write_event(ring_data_t *data, blockstore_op_t *op);
 
     // Sync
-    int dequeue_sync(blockstore_op_t *op);
+    int continue_sync(blockstore_op_t *op, bool queue_has_in_progress_sync);
     void handle_sync_event(ring_data_t *data, blockstore_op_t *op);
-    int continue_sync(blockstore_op_t *op);
-    void ack_one_sync(blockstore_op_t *op);
-    int ack_sync(blockstore_op_t *op);
+    void ack_sync(blockstore_op_t *op);
 
     // Stabilize
     int dequeue_stable(blockstore_op_t *op);
diff --git a/src/blockstore_rollback.cpp b/src/blockstore_rollback.cpp
index 3040a360..58249719 100644
--- a/src/blockstore_rollback.cpp
+++ b/src/blockstore_rollback.cpp
@@ -50,7 +50,7 @@ skip_ov:
                 {
                     op->retval = -EBUSY;
                     FINISH_OP(op);
-                    return 1;
+                    return 2;
                 }
                 if (dirty_it == dirty_db.begin())
                 {
@@ -66,7 +66,7 @@ skip_ov:
         // Already rolled back
         op->retval = 0;
         FINISH_OP(op);
-        return 1;
+        return 2;
     }
     // Check journal space
     blockstore_journal_check_t space_check(this);
@@ -151,7 +151,7 @@ resume_5:
     // Acknowledge op
     op->retval = 0;
     FINISH_OP(op);
-    return 1;
+    return 2;
 }
 
 void blockstore_impl_t::mark_rolled_back(const obj_ver_id & ov)
@@ -216,10 +216,7 @@ void blockstore_impl_t::handle_rollback_event(ring_data_t *data, blockstore_op_t
     if (PRIV(op)->pending_ops == 0)
     {
         PRIV(op)->op_state++;
-        if (!continue_rollback(op))
-        {
-            submit_queue.push_front(op);
-        }
+        ringloop->wakeup();
     }
 }
 
diff --git a/src/blockstore_stable.cpp b/src/blockstore_stable.cpp
index 3a520ee9..86bc31c3 100644
--- a/src/blockstore_stable.cpp
+++ b/src/blockstore_stable.cpp
@@ -60,7 +60,7 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
                 // No such object version
                 op->retval = -ENOENT;
                 FINISH_OP(op);
-                return 1;
+                return 2;
             }
             else
             {
@@ -77,7 +77,7 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
             // Object not synced yet. Caller must sync it first
             op->retval = -EBUSY;
             FINISH_OP(op);
-            return 1;
+            return 2;
         }
         else if (!IS_STABLE(dirty_it->second.state))
         {
@@ -89,7 +89,7 @@ int blockstore_impl_t::dequeue_stable(blockstore_op_t *op)
         // Already stable
         op->retval = 0;
         FINISH_OP(op);
-        return 1;
+        return 2;
     }
     // Check journal space
     blockstore_journal_check_t space_check(this);
@@ -176,7 +176,7 @@ resume_5:
     // Acknowledge op
     op->retval = 0;
     FINISH_OP(op);
-    return 1;
+    return 2;
 }
 
 void blockstore_impl_t::mark_stable(const obj_ver_id & v)
@@ -228,9 +228,6 @@ void blockstore_impl_t::handle_stable_event(ring_data_t *data, blockstore_op_t *
     if (PRIV(op)->pending_ops == 0)
     {
         PRIV(op)->op_state++;
-        if (!continue_stable(op))
-        {
-            submit_queue.push_front(op);
-        }
+        ringloop->wakeup();
     }
 }
diff --git a/src/blockstore_sync.cpp b/src/blockstore_sync.cpp
index 348548f5..bcce8607 100644
--- a/src/blockstore_sync.cpp
+++ b/src/blockstore_sync.cpp
@@ -12,8 +12,15 @@
 #define SYNC_JOURNAL_SYNC_SENT 7
 #define SYNC_DONE 8
 
-int blockstore_impl_t::dequeue_sync(blockstore_op_t *op)
+int blockstore_impl_t::continue_sync(blockstore_op_t *op, bool queue_has_in_progress_sync)
 {
+    if (immediate_commit == IMMEDIATE_ALL)
+    {
+        // We can return immediately because sync is only dequeued after all previous writes
+        op->retval = 0;
+        FINISH_OP(op);
+        return 2;
+    }
     if (PRIV(op)->op_state == 0)
     {
         stop_sync_submitted = false;
@@ -29,34 +36,15 @@ int blockstore_impl_t::dequeue_sync(blockstore_op_t *op)
             PRIV(op)->op_state = SYNC_HAS_SMALL;
         else
             PRIV(op)->op_state = SYNC_DONE;
-        // Always add sync to in_progress_syncs because we clear unsynced_big_writes and unsynced_small_writes
-        PRIV(op)->prev_sync_count = in_progress_syncs.size();
-        PRIV(op)->in_progress_ptr = in_progress_syncs.insert(in_progress_syncs.end(), op);
     }
-    continue_sync(op);
-    // Always dequeue because we always add syncs to in_progress_syncs
-    return 1;
-}
-
-int blockstore_impl_t::continue_sync(blockstore_op_t *op)
-{
-    auto cb = [this, op](ring_data_t *data) { handle_sync_event(data, op); };
     if (PRIV(op)->op_state == SYNC_HAS_SMALL)
     {
         // No big writes, just fsync the journal
-        for (; PRIV(op)->sync_small_checked < PRIV(op)->sync_small_writes.size(); PRIV(op)->sync_small_checked++)
-        {
-            if (IS_IN_FLIGHT(dirty_db[PRIV(op)->sync_small_writes[PRIV(op)->sync_small_checked]].state))
-            {
-                // Wait for small inflight writes to complete
-                return 0;
-            }
-        }
         if (journal.sector_info[journal.cur_sector].dirty)
         {
             // Write out the last journal sector if it happens to be dirty
             BS_SUBMIT_GET_ONLY_SQE(sqe);
-            prepare_journal_sector_write(journal, journal.cur_sector, sqe, cb);
+            prepare_journal_sector_write(journal, journal.cur_sector, sqe, [this, op](ring_data_t *data) { handle_sync_event(data, op); });
             PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 1 + journal.cur_sector;
             PRIV(op)->pending_ops = 1;
             PRIV(op)->op_state = SYNC_JOURNAL_WRITE_SENT;
@@ -69,21 +57,13 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
     }
     if (PRIV(op)->op_state == SYNC_HAS_BIG)
     {
-        for (; PRIV(op)->sync_big_checked < PRIV(op)->sync_big_writes.size(); PRIV(op)->sync_big_checked++)
-        {
-            if (IS_IN_FLIGHT(dirty_db[PRIV(op)->sync_big_writes[PRIV(op)->sync_big_checked]].state))
-            {
-                // Wait for big inflight writes to complete
-                return 0;
-            }
-        }
         // 1st step: fsync data
         if (!disable_data_fsync)
         {
             BS_SUBMIT_GET_SQE(sqe, data);
             my_uring_prep_fsync(sqe, data_fd, IORING_FSYNC_DATASYNC);
             data->iov = { 0 };
-            data->callback = cb;
+            data->callback = [this, op](ring_data_t *data) { handle_sync_event(data, op); };
             PRIV(op)->min_flushed_journal_sector = PRIV(op)->max_flushed_journal_sector = 0;
             PRIV(op)->pending_ops = 1;
             PRIV(op)->op_state = SYNC_DATA_SYNC_SENT;
@@ -96,14 +76,6 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
     }
     if (PRIV(op)->op_state == SYNC_DATA_SYNC_DONE)
     {
-        for (; PRIV(op)->sync_small_checked < PRIV(op)->sync_small_writes.size(); PRIV(op)->sync_small_checked++)
-        {
-            if (IS_IN_FLIGHT(dirty_db[PRIV(op)->sync_small_writes[PRIV(op)->sync_small_checked]].state))
-            {
-                // Wait for small inflight writes to complete
-                return 0;
-            }
-        }
         // 2nd step: Data device is synced, prepare & write journal entries
         // Check space in the journal and journal memory buffers
         blockstore_journal_check_t space_check(this);
@@ -127,7 +99,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
             {
                 if (cur_sector == -1)
                     PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
-                prepare_journal_sector_write(journal, journal.cur_sector, sqe[s++], cb);
+                prepare_journal_sector_write(journal, journal.cur_sector, sqe[s++], [this, op](ring_data_t *data) { handle_sync_event(data, op); });
                 cur_sector = journal.cur_sector;
             }
             journal_entry_big_write *je = (journal_entry_big_write*)prefill_single_journal_entry(
@@ -152,7 +124,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
             journal.crc32_last = je->crc32;
             it++;
         }
-        prepare_journal_sector_write(journal, journal.cur_sector, sqe[s++], cb);
+        prepare_journal_sector_write(journal, journal.cur_sector, sqe[s++], [this, op](ring_data_t *data) { handle_sync_event(data, op); });
         assert(s == space_check.sectors_to_write);
         if (cur_sector == -1)
             PRIV(op)->min_flushed_journal_sector = 1 + journal.cur_sector;
@@ -168,7 +140,7 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
             BS_SUBMIT_GET_SQE(sqe, data);
             my_uring_prep_fsync(sqe, journal.fd, IORING_FSYNC_DATASYNC);
             data->iov = { 0 };
-            data->callback = cb;
+            data->callback = [this, op](ring_data_t *data) { handle_sync_event(data, op); };
             PRIV(op)->pending_ops = 1;
             PRIV(op)->op_state = SYNC_JOURNAL_SYNC_SENT;
             return 1;
@@ -178,9 +150,10 @@ int blockstore_impl_t::continue_sync(blockstore_op_t *op)
             PRIV(op)->op_state = SYNC_DONE;
         }
     }
-    if (PRIV(op)->op_state == SYNC_DONE)
+    if (PRIV(op)->op_state == SYNC_DONE && !queue_has_in_progress_sync)
     {
-        return ack_sync(op);
+        ack_sync(op);
+        return 2;
     }
     return 1;
 }
@@ -212,42 +185,16 @@ void blockstore_impl_t::handle_sync_event(ring_data_t *data, blockstore_op_t *op
         else if (PRIV(op)->op_state == SYNC_JOURNAL_SYNC_SENT)
         {
             PRIV(op)->op_state = SYNC_DONE;
-            ack_sync(op);
         }
         else
         {
             throw std::runtime_error("BUG: unexpected sync op state");
         }
+        ringloop->wakeup();
     }
 }
 
-int blockstore_impl_t::ack_sync(blockstore_op_t *op)
-{
-    if (PRIV(op)->op_state == SYNC_DONE && PRIV(op)->prev_sync_count == 0)
-    {
-        // Remove dependency of subsequent syncs
-        auto it = PRIV(op)->in_progress_ptr;
-        int done_syncs = 1;
-        ++it;
-        // Acknowledge sync
-        ack_one_sync(op);
-        while (it != in_progress_syncs.end())
-        {
-            auto & next_sync = *it++;
-            PRIV(next_sync)->prev_sync_count -= done_syncs;
-            if (PRIV(next_sync)->prev_sync_count == 0 && PRIV(next_sync)->op_state == SYNC_DONE)
-            {
-                done_syncs++;
-                // Acknowledge next_sync
-                ack_one_sync(next_sync);
-            }
-        }
-        return 2;
-    }
-    return 0;
-}
-
-void blockstore_impl_t::ack_one_sync(blockstore_op_t *op)
+void blockstore_impl_t::ack_sync(blockstore_op_t *op)
 {
     // Handle states
     for (auto it = PRIV(op)->sync_big_writes.begin(); it != PRIV(op)->sync_big_writes.end(); it++)
@@ -295,7 +242,6 @@ void blockstore_impl_t::ack_one_sync(blockstore_op_t *op)
             }
         }
     }
-    in_progress_syncs.erase(PRIV(op)->in_progress_ptr);
     op->retval = 0;
     FINISH_OP(op);
 }
diff --git a/src/blockstore_write.cpp b/src/blockstore_write.cpp
index deb877f5..42f1689a 100644
--- a/src/blockstore_write.cpp
+++ b/src/blockstore_write.cpp
@@ -170,7 +170,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         {
             // This is the flag value used to cancel operations
             FINISH_OP(op);
-            return 1;
+            return 2;
         }
         // Restore original low version number for unblocked operations
 #ifdef BLOCKSTORE_DEBUG
@@ -183,7 +183,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
             // Original version is still invalid
             // All subsequent writes to the same object must be canceled too
             cancel_all_writes(op, dirty_it, -EEXIST);
-            return 1;
+            return 2;
         }
         op->version = PRIV(op)->real_version;
         PRIV(op)->real_version = 0;
@@ -217,7 +217,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
                 return 0;
             }
             cancel_all_writes(op, dirty_it, -ENOSPC);
-            return 1;
+            return 2;
         }
         write_iodepth++;
         BS_SUBMIT_GET_SQE(sqe, data);
@@ -370,7 +370,7 @@ int blockstore_impl_t::dequeue_write(blockstore_op_t *op)
         if (!PRIV(op)->pending_ops)
         {
             PRIV(op)->op_state = 4;
-            continue_write(op);
+            return continue_write(op);
         }
         else
         {
@@ -384,17 +384,21 @@ int blockstore_impl_t::continue_write(blockstore_op_t *op)
 {
     io_uring_sqe *sqe = NULL;
     journal_entry_big_write *je;
+    int op_state = PRIV(op)->op_state;
+    if (op_state != 2 && op_state != 4)
+    {
+        // In progress
+        return 1;
+    }
     auto dirty_it = dirty_db.find((obj_ver_id){
         .oid = op->oid,
         .version = op->version,
     });
     assert(dirty_it != dirty_db.end());
-    if (PRIV(op)->op_state == 2)
+    if (op_state == 2)
         goto resume_2;
-    else if (PRIV(op)->op_state == 4)
+    else if (op_state == 4)
         goto resume_4;
-    else
-        return 1;
 resume_2:
     // Only for the immediate_commit mode: prepare and submit big_write journal entry
     sqe = get_sqe();
@@ -464,7 +468,7 @@ resume_4:
     op->retval = op->len;
     write_iodepth--;
     FINISH_OP(op);
-    return 1;
+    return 2;
 }
 
 void blockstore_impl_t::handle_write_event(ring_data_t *data, blockstore_op_t *op)
@@ -483,10 +487,7 @@ void blockstore_impl_t::handle_write_event(ring_data_t *data, blockstore_op_t *o
     {
         release_journal_sectors(op);
         PRIV(op)->op_state++;
-        if (!continue_write(op))
-        {
-            submit_queue.push_front(op);
-        }
+        ringloop->wakeup();
     }
 }
 
@@ -524,6 +525,10 @@ void blockstore_impl_t::release_journal_sectors(blockstore_op_t *op)
 
 int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
 {
+    if (PRIV(op)->op_state)
+    {
+        return continue_write(op);
+    }
     auto dirty_it = dirty_db.find((obj_ver_id){
         .oid = op->oid,
         .version = op->version,
@@ -593,7 +598,7 @@ int blockstore_impl_t::dequeue_del(blockstore_op_t *op)
     if (!PRIV(op)->pending_ops)
     {
         PRIV(op)->op_state = 4;
-        continue_write(op);
+        return continue_write(op);
     }
     else
     {