fsync directory after creating current file in NewDB()

Summary: One of our users reported current file corruption. The machine was rebooted during the time. This is the only think I can think of which could cause current file corruption. Just add this paranoid check.

Test Plan: make all check

Reviewers: haobo, igor

Reviewed By: haobo

CC: yhchiang, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D18495

db/db_impl.cc

@@ -487,7 +487,7 @@ Status DBImpl::NewDB() {
   }
   if (s.ok()) {
     // Make "CURRENT" file that points to the new manifest file.
-    s = SetCurrentFile(env_, dbname_, 1);
+    s = SetCurrentFile(env_, dbname_, 1, db_directory_.get());
   } else {
     env_->DeleteFile(manifest);
   }

db/filename.cc

@@ -226,7 +226,8 @@ bool ParseFileName(const std::string& fname,
 }
 
 Status SetCurrentFile(Env* env, const std::string& dbname,
-                      uint64_t descriptor_number) {
+                      uint64_t descriptor_number,
+                      Directory* directory_to_fsync) {
   // Remove leading "dbname/" and add newline to manifest file name
   std::string manifest = DescriptorFileName(dbname, descriptor_number);
   Slice contents = manifest;
@@ -237,7 +238,11 @@ Status SetCurrentFile(Env* env, const std::string& dbname,
   if (s.ok()) {
     s = env->RenameFile(tmp, CurrentFileName(dbname));
   }
-  if (!s.ok()) {
+  if (s.ok()) {
+    if (directory_to_fsync != nullptr) {
+      directory_to_fsync->Fsync();
+    }
+  } else {
     env->DeleteFile(tmp);
   }
   return s;

db/filename.h

@@ -20,6 +20,7 @@
 namespace rocksdb {
 
 class Env;
+class Directory;
 
 enum FileType {
   kLogFile,
@@ -100,7 +101,8 @@ extern bool ParseFileName(const std::string& filename,
 // Make the CURRENT file point to the descriptor file with the
 // specified number.
 extern Status SetCurrentFile(Env* env, const std::string& dbname,
-                             uint64_t descriptor_number);
+                             uint64_t descriptor_number,
+                             Directory* directory_to_fsync);
 
 // Make the IDENTITY file for the db
 extern Status SetIdentityFile(Env* env, const std::string& dbname);

db/repair.cc

@@ -363,7 +363,7 @@ class Repairer {
       // Install new manifest
       status = env_->RenameFile(tmp, DescriptorFileName(dbname_, 1));
       if (status.ok()) {
-        status = SetCurrentFile(env_, dbname_, 1);
+        status = SetCurrentFile(env_, dbname_, 1, nullptr);
       } else {
         env_->DeleteFile(tmp);
       }

db/version_set.cc

@@ -1731,7 +1731,8 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
     // If we just created a new descriptor file, install it by writing a
     // new CURRENT file that points to it.
     if (s.ok() && new_descriptor_log) {
-      s = SetCurrentFile(env_, dbname_, pending_manifest_file_number_);
+      s = SetCurrentFile(env_, dbname_, pending_manifest_file_number_,
+                         db_directory);
       if (s.ok() && pending_manifest_file_number_ > manifest_file_number_) {
         // delete old manifest file
         Log(options_->info_log,
@@ -1741,9 +1742,6 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
         // of it later
         env_->DeleteFile(DescriptorFileName(dbname_, manifest_file_number_));
       }
-      if (!options_->disableDataSync && db_directory != nullptr) {
-        db_directory->Fsync();
-      }
     }
 
     if (s.ok()) {