From 31ec3fa8f5f47a3933a632e6801c53095409a50b Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Sun, 22 Oct 2023 16:56:46 +0300
Subject: [PATCH] Allow to track multiple updates per block (it should never
 happen though)

---
 src/kv_db.cpp | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/kv_db.cpp b/src/kv_db.cpp
index b10c9b05..e430262b 100644
--- a/src/kv_db.cpp
+++ b/src/kv_db.cpp
@@ -82,7 +82,7 @@ struct kv_block_t
     std::map<std::string, std::string> data;
 
     // set during update
-    bool updating;
+    int updating = 0;
     int change_type;
     std::string change_key, change_value;
     std::string change_rh;
@@ -625,8 +625,10 @@ void kv_db_t::run_continue_update(uint64_t offset)
 
 void kv_db_t::stop_updating(kv_block_t *blk)
 {
-    blk->updating = false;
-    run_continue_update(blk->offset);
+    assert(blk->updating > 0);
+    blk->updating--;
+    if (!blk->updating)
+        run_continue_update(blk->offset);
 }
 
 static void del_block_level(kv_db_t *db, kv_block_t *blk)
@@ -646,7 +648,7 @@ static void invalidate(kv_db_t *db, uint64_t offset, uint64_t version)
         auto b_it = db->block_cache.lower_bound(offset/db->ino_block_size * db->ino_block_size);
         while (b_it != db->block_cache.end() && b_it->first/db->ino_block_size == offset/db->ino_block_size)
         {
-            if (b_it->second.updating)
+            if (b_it->second.updating > 0)
             {
                 // do not forget blocks during modification
                 b_it++;
@@ -1073,7 +1075,7 @@ static kv_block_t *create_new_block(kv_db_t *db, kv_block_t *old_blk, const std:
     blk->level = old_blk->level;
     blk->type = old_blk->type == KV_LEAF_SPLIT || old_blk->type == KV_LEAF ? KV_LEAF : KV_INT;
     blk->offset = new_offset;
-    blk->updating = true;
+    blk->updating++;
     blk->key_ge = right ? separator : old_blk->key_ge;
     blk->key_lt = right ? old_blk->key_lt : separator;
     blk->data.insert(right ? old_blk->data.lower_bound(separator) : old_blk->data.begin(),
@@ -1269,7 +1271,7 @@ void kv_op_t::create_root()
     blk->data[key] = value;
     blk->set_data_size();
     add_block_level(db, blk);
-    blk->updating = true;
+    blk->updating++;
     write_block(db, blk, [=](int res)
     {
         db->stop_updating(blk);
@@ -1384,7 +1386,7 @@ void kv_op_t::update_block(int path_pos, bool is_delete, const std::string & key
             abort();
         }
     }
-    blk->updating = true;
+    blk->updating++;
     if (is_delete || (blk->data_size + kv_block_t::kv_size(key, value) - rm_size) < db->kv_block_size)
     {
         // New item fits.
@@ -1463,6 +1465,7 @@ void kv_op_t::update_block(int path_pos, bool is_delete, const std::string & key
                 new_root->data[""] = std::string((char*)&left_blk->offset, sizeof(left_blk->offset));
                 new_root->data[separator] = std::string((char*)&right_blk->offset, sizeof(right_blk->offset));
                 new_root->set_data_size();
+                new_root->updating++;
                 write_block(db, new_root, [=](int write_res)
                 {
                     if (write_res < 0)