Rename DBImpl::log_dir_unsynced_ to log_dir_synced_

Summary: log_dir_unsynced_ is a confusing name. Rename it to log_dir_synced_ and flip the value.

Test Plan: Run ./fault_injection_test

Reviewers: rven, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D32235

db/db_impl.cc

@@ -201,7 +201,7 @@ DBImpl::DBImpl(const DBOptions& options, const std::string& dbname)
       shutting_down_(false),
       bg_cv_(&mutex_),
       logfile_number_(0),
-      log_dir_unsynced_(true),
+      log_dir_synced_(false),
       log_empty_(true),
       default_cf_handle_(nullptr),
       total_log_size_(0),
@@ -3101,13 +3101,13 @@ Status DBImpl::Write(const WriteOptions& write_options, WriteBatch* my_batch) {
           } else {
             status = log_->file()->Sync();
           }
-          if (status.ok() && log_dir_unsynced_) {
+          if (status.ok() && !log_dir_synced_) {
             // We only sync WAL directory the first time WAL syncing is
             // requested, so that in case users never turn on WAL sync,
             // we can avoid the disk I/O in the write code path.
             status = directories_.GetWalDir()->Fsync();
           }
-          log_dir_unsynced_ = false;
+          log_dir_synced_ = true;
         }
       }
       if (status.ok()) {
@@ -3250,7 +3250,7 @@ Status DBImpl::SetNewMemtableAndNewLogFile(ColumnFamilyData* cfd,
         lfile->SetPreallocationBlockSize(
             1.1 * mutable_cf_options.write_buffer_size);
         new_log = new log::Writer(std::move(lfile));
-        log_dir_unsynced_ = true;
+        log_dir_synced_ = false;
       }
     }
 

db/db_impl.h

@@ -422,7 +422,7 @@ class DBImpl : public DB {
   port::CondVar bg_cv_;
   uint64_t logfile_number_;
   unique_ptr<log::Writer> log_;
-  bool log_dir_unsynced_;
+  bool log_dir_synced_;
   bool log_empty_;
   ColumnFamilyHandleImpl* default_cf_handle_;
   InternalStats* default_cf_internal_stats_;