From 6e20d541b0fb351fcdd0b7f8d01076df39b40d38 Mon Sep 17 00:00:00 2001
From: Alexander Rutkovsky <alexvru@ydb.tech>
Date: Thu, 3 Oct 2024 10:53:23 +0300
Subject: [PATCH] Temporarily fix data race in PDisk (#9988)

---
 .../pdisk/blobstorage_pdisk_impl.cpp          |  4 ++++
 .../pdisk/blobstorage_pdisk_impl_metadata.cpp | 12 ++++++++--
 .../pdisk/blobstorage_pdisk_request_id.h      |  2 ++
 .../pdisk/blobstorage_pdisk_requestimpl.h     | 22 +++++++++++++++++++
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
index 3557c6f49811..0ab6abf3075d 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl.cpp
@@ -2485,6 +2485,9 @@ void TPDisk::ProcessFastOperationsQueue() {
             case ERequestType::RequestPushUnformattedMetadataSector:
                 ProcessPushUnformattedMetadataSector(static_cast<TPushUnformattedMetadataSector&>(*req));
                 break;
+            case ERequestType::RequestContinueReadMetadata:
+                static_cast<TContinueReadMetadata&>(*req).Execute(PCtx->ActorSystem);
+                break;
             default:
                 Y_FAIL_S("Unexpected request type# " << (ui64)req->GetType());
                 break;
@@ -3078,6 +3081,7 @@ bool TPDisk::PreprocessRequest(TRequestBase *request) {
         case ERequestType::RequestPushUnformattedMetadataSector:
         case ERequestType::RequestReadMetadata:
         case ERequestType::RequestWriteMetadata:
+        case ERequestType::RequestContinueReadMetadata:
             break;
         case ERequestType::RequestStopDevice:
             BlockDevice->Stop();
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_metadata.cpp b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_metadata.cpp
index ca4ab7f9e0cc..d604b3232a29 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_metadata.cpp
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_impl_metadata.cpp
@@ -59,8 +59,16 @@ namespace NKikimr::NPDisk {
                         const size_t bytesToRead = PDisk->Format.RoundUpToSectorSize(sizeof(TMetadataHeader) + header->Length);
                         Buffer = TRcBuf::UninitializedPageAligned(bytesToRead); // __header is not valid anymore__
                         const ui64 offset = PDisk->Format.Offset(Req->Key.ChunkIdx, Req->Key.OffsetInSectors);
-                        PDisk->BlockDevice->PreadAsync(GetBuffer(), bytesToRead, offset, this, Req->ReqId, nullptr);
-                        return;
+                        auto buffer = GetBuffer();
+                        auto reqId = Req->ReqId;
+                        auto callback = [buffer, bytesToRead, offset, this, reqId](bool success, TActorSystem *actorSystem) {
+                            if (success) {
+                                PDisk->BlockDevice->PreadAsync(buffer, bytesToRead, offset, this, reqId, nullptr);
+                            } else {
+                                Release(actorSystem);
+                            }
+                        };
+                        return PDisk->InputRequest(PDisk->ReqCreator.CreateFromArgs<TContinueReadMetadata>(callback));
                     }
                 } else {
                     Req->ErrorReason = "header checksum does not pass validation";
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_request_id.h b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_request_id.h
index b5e83bbcdc05..f186544538b5 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_request_id.h
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_request_id.h
@@ -88,6 +88,7 @@ struct TReqId {
         WriteMetadata = 69,
         WriteMetadataResult = 70,
         PushUnformattedMetadataSector = 71,
+        ContinueReadMetadata = 72,
     };
 
     // 56 bit idx, 8 bit source
@@ -151,6 +152,7 @@ enum class ERequestType {
     RequestWriteMetadata,
     RequestWriteMetadataResult,
     RequestPushUnformattedMetadataSector,
+    RequestContinueReadMetadata,
 };
 
 inline IOutputStream& operator <<(IOutputStream& out, const TReqId& reqId) {
diff --git a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_requestimpl.h b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_requestimpl.h
index 32c4e6afcbb6..bd7dea1db7f8 100644
--- a/ydb/core/blobstorage/pdisk/blobstorage_pdisk_requestimpl.h
+++ b/ydb/core/blobstorage/pdisk/blobstorage_pdisk_requestimpl.h
@@ -1095,5 +1095,27 @@ class TPushUnformattedMetadataSector : public TRequestBase {
     }
 };
 
+class TContinueReadMetadata : public TRequestBase {
+    std::function<void(bool, TActorSystem*)> Callback;
+
+public:
+    TContinueReadMetadata(std::function<void(bool, TActorSystem*)> callback, TAtomicBase reqIdx)
+        : TRequestBase({}, TReqId(TReqId::ContinueReadMetadata, reqIdx), OwnerSystem, 0, NPriInternal::Other)
+        , Callback(std::move(callback))
+    {}
+
+    ERequestType GetType() const override {
+        return ERequestType::RequestContinueReadMetadata;
+    }
+
+    void Execute(TActorSystem *actorSystem) {
+        Callback(true, actorSystem);
+    }
+
+    void Abort(TActorSystem *actorSystem) override {
+        Callback(false, actorSystem);
+    }
+};
+
 } // NPDisk
 } // NKikimr