From 3381e2c3e7b15acb7d43420a6a5486015903eaff Mon Sep 17 00:00:00 2001
From: Reid Horuff <reidhoruff@gmail.com>
Date: Mon, 16 Nov 2015 12:34:55 -0800
Subject: [PATCH] Handle multiple calls to DBImpl::PauseBackgroundWork() and
 DBImpl::ContinueBackgroundWork()

Summary: Handle multiple calls to DBImpl::PauseBackgroundWork() and DBImpl::ContinueBackgroundWork()

Test Plan: rocksdb.information_schema handles this case.

Reviewers: igor

Reviewed By: igor

Subscribers: hermanlee4, jkedgar, dhruba

Differential Revision: https://reviews.facebook.net/D50781
---
 db/db_impl.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/db/db_impl.cc b/db/db_impl.cc
index 2f105e1a2..30da7a934 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -1850,6 +1850,9 @@ Status DBImpl::PauseBackgroundWork() {
 
 Status DBImpl::ContinueBackgroundWork() {
   InstrumentedMutexLock guard_lock(&mutex_);
+  if (bg_work_paused_ == 0) {
+    return Status::InvalidArgument();
+  }
   assert(bg_work_paused_ > 0);
   bg_work_paused_--;
   if (bg_work_paused_ == 0) {