Fix a data race affecting the background error status (#12910)

Summary:
Pull Request resolved: https://github.com/facebook/rocksdb/pull/12910

There is currently a call to `GetBGError()` in `DBImpl::WriteImplWALOnly()` where the DB mutex is (incorrectly) not held, leading to a data race. Technically, we could acquire the mutex here but instead, the patch removes the affected check altogether, since the same check is already performed (in a thread-safe manner) in the subsequent call to `PreprocessWrite()`.

Reviewed By: cbi42

Differential Revision: D60682008

fbshipit-source-id: 54b67975dcf57d67c068cac71e8ada09a1793ec5

1 files changed, 7 insertions, 11 deletions

diff --git a/db/db_impl/db_impl_write.cc b/db/db_impl/db_impl_write.cc
index ec5283ad9..d6899502a 100644
--- a/db/db_impl/db_impl_write.cc
+++ b/db/db_impl/db_impl_write.cc
@@ -969,21 +969,17 @@ Status DBImpl::WriteImplWALOnly(
   assert(w.state == WriteThread::STATE_GROUP_LEADER);
 
   if (publish_last_seq == kDoPublishLastSeq) {
-    Status status;
-
     // Currently we only use kDoPublishLastSeq in unordered_write
     assert(immutable_db_options_.unordered_write);
-    WriteContext write_context;
-    if (error_handler_.IsDBStopped()) {
-      status = error_handler_.GetBGError();
-    }
+
     // TODO(myabandeh): Make preliminary checks thread-safe so we could do them
     // without paying the cost of obtaining the mutex.
-    if (status.ok()) {
-      LogContext log_context;
-      status = PreprocessWrite(write_options, &log_context, &write_context);
-      WriteStatusCheckOnLocked(status);
-    }
+    LogContext log_context;
+    WriteContext write_context;
+    Status status =
+        PreprocessWrite(write_options, &log_context, &write_context);
+    WriteStatusCheckOnLocked(status);
+
     if (!status.ok()) {
       WriteThread::WriteGroup write_group;
       write_thread->EnterAsBatchGroupLeader(&w, &write_group);