SERVER-4243 prevent write lock in network rs thread from blocking readers during fsync

1 files changed, 22 insertions, 0 deletions

diff --git a/src/mongo/db/commands/fsync.h b/src/mongo/db/commands/fsync.h
new file mode 100644
index 00000000000..2e57cbda403
--- /dev/null
+++ b/src/mongo/db/commands/fsync.h
@@ -0,0 +1,22 @@
+/**
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+namespace mongo {
+    // Use this for blocking during an fsync-and-lock
+    extern SimpleMutex filesLockedFsync;
+    bool lockedForWriting();
+}