From 856ad79a02ba7d63ab582920da08923581d4db26 Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Sun, 2 Nov 2025 12:58:10 +0300
Subject: [PATCH] Fix mark_completed_lsns for enabled fsyncs

---
 src/blockstore/blockstore_heap.cpp | 12 +++++++-----
 src/blockstore/blockstore_heap.h   |  2 +-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/blockstore/blockstore_heap.cpp b/src/blockstore/blockstore_heap.cpp
index 11965a69..1cfc7041 100644
--- a/src/blockstore/blockstore_heap.cpp
+++ b/src/blockstore/blockstore_heap.cpp
@@ -1501,7 +1501,7 @@ void blockstore_heap_t::complete_block_write(uint32_t block_num)
             assert(!(it->flags & HEAP_INFLIGHT_DONE));
             it->flags |= HEAP_INFLIGHT_DONE;
         }
-        mark_completed_lsns();
+        mark_completed_lsns(mod_lsn);
     }
 }
 
@@ -1938,7 +1938,7 @@ void blockstore_heap_t::push_inflight_lsn(uint64_t lsn, heap_entry_t *wr, uint64
     }
 }
 
-void blockstore_heap_t::mark_completed_lsns()
+void blockstore_heap_t::mark_completed_lsns(uint64_t mod_lsn)
 {
     if (dsk->disable_meta_fsync && dsk->disable_journal_fsync)
     {
@@ -1956,10 +1956,11 @@ void blockstore_heap_t::mark_completed_lsns()
             first_inflight_lsn++;
         }
     }
-    else
+    else if (mod_lsn == completed_lsn+1)
     {
-        // Only advanced completed_lsn
-        for (auto it = inflight_lsn.begin(); it != inflight_lsn.end() && (it->flags & HEAP_INFLIGHT_DONE); it++)
+        // Only advance completed_lsn
+        assert(inflight_lsn.size() > mod_lsn-first_inflight_lsn);
+        for (auto it = inflight_lsn.begin()+(mod_lsn-first_inflight_lsn); it != inflight_lsn.end() && (it->flags & HEAP_INFLIGHT_DONE); it++)
         {
             completed_lsn++;
         }
@@ -1974,6 +1975,7 @@ void blockstore_heap_t::mark_lsn_fsynced(uint64_t lsn)
         assert(lsn <= completed_lsn);
         while (lsn >= first_inflight_lsn)
         {
+            assert(inflight_lsn.size() > 0);
             apply_inflight(inflight_lsn.front());
             inflight_lsn.pop_front();
             first_inflight_lsn++;
diff --git a/src/blockstore/blockstore_heap.h b/src/blockstore/blockstore_heap.h
index 470e6034..c2387144 100644
--- a/src/blockstore/blockstore_heap.h
+++ b/src/blockstore/blockstore_heap.h
@@ -207,7 +207,7 @@ class blockstore_heap_t
     void mark_garbage_up_to(heap_entry_t *wr);
     void mark_garbage(uint32_t block_num, heap_entry_t *prev_wr, uint32_t used_big);
     void push_inflight_lsn(uint64_t lsn, heap_entry_t *wr, uint64_t flags);
-    void mark_completed_lsns();
+    void mark_completed_lsns(uint64_t mod_lsn);
     void apply_inflight(heap_inflight_lsn_t & inflight);
 public:
     blockstore_heap_t(blockstore_disk_t *dsk, uint8_t *buffer_area, int log_level = 0);