Add status checks during DB::Open (#6380)

Summary:
Several statuses were not checked during DB::Open.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6380

Test Plan: make check

Differential Revision: D19780237

Pulled By: cheng-chang

fbshipit-source-id: c8d189d20344bd1607890dd1449345bda2ef96b9

db/db_impl/db_impl_open.cc

@@ -442,19 +442,19 @@ Status DBImpl::Recover(
       assert(s.IsIOError());
       return s;
     }
-    GetDbIdentityFromIdentityFile(&db_id_);
-    if (immutable_db_options_.write_dbid_to_manifest) {
+    s = GetDbIdentityFromIdentityFile(&db_id_);
+    if (immutable_db_options_.write_dbid_to_manifest && s.ok()) {
       VersionEdit edit;
       edit.SetDBId(db_id_);
       Options options;
       MutableCFOptions mutable_cf_options(options);
       versions_->db_id_ = db_id_;
-      versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
+      s = versions_->LogAndApply(versions_->GetColumnFamilySet()->GetDefault(),
                              mutable_cf_options, &edit, &mutex_, nullptr,
                              false);
     }
   } else {
-    SetIdentityFile(env_, dbname_, db_id_);
+    s = SetIdentityFile(env_, dbname_, db_id_);
   }
 
   if (immutable_db_options_.paranoid_checks && s.ok()) {
@@ -474,16 +474,16 @@ Status DBImpl::Recover(
     s = InitPersistStatsColumnFamily();
   }
 
-  // Initial max_total_in_memory_state_ before recovery logs. Log recovery
-  // may check this value to decide whether to flush.
-  max_total_in_memory_state_ = 0;
-  for (auto cfd : *versions_->GetColumnFamilySet()) {
-    auto* mutable_cf_options = cfd->GetLatestMutableCFOptions();
-    max_total_in_memory_state_ += mutable_cf_options->write_buffer_size *
-                                  mutable_cf_options->max_write_buffer_number;
-  }
-
   if (s.ok()) {
+    // Initial max_total_in_memory_state_ before recovery logs. Log recovery
+    // may check this value to decide whether to flush.
+    max_total_in_memory_state_ = 0;
+    for (auto cfd : *versions_->GetColumnFamilySet()) {
+      auto* mutable_cf_options = cfd->GetLatestMutableCFOptions();
+      max_total_in_memory_state_ += mutable_cf_options->write_buffer_size *
+                                    mutable_cf_options->max_write_buffer_number;
+    }
+
     SequenceNumber next_sequence(kMaxSequenceNumber);
     default_cf_handle_ = new ColumnFamilyHandleImpl(
         versions_->GetColumnFamilySet()->GetDefault(), this, &mutex_);