Temp Fix of LogBuffer flushing

Summary: To temp fix the log buffer flushing. Flush the buffer inside the lock. Clean the trunk before we find an eventual fix.

Test Plan: make all check

Reviewers: haobo, igor

Reviewed By: igor

CC: ljin, leveldb, yhchiang

Differential Revision: https://reviews.facebook.net/D16791

db/db_impl.cc

@@ -1923,13 +1923,13 @@ void DBImpl::BackgroundCallFlush() {
     if (madeProgress) {
       MaybeScheduleFlushOrCompaction();
     }
+    log_buffer.FlushBufferToLog();
     bg_cv_.SignalAll();
     // IMPORTANT: there should be no code after calling SignalAll. This call may
     // signal the DB destructor that it's OK to proceed with destruction. In
     // that case, all DB variables will be dealloacated and referencing them
     // will cause trouble.
   }
-  log_buffer.FlushBufferToLog();
 }
 
 
@@ -1996,13 +1996,13 @@ void DBImpl::BackgroundCallCompaction() {
     if (madeProgress) {
       MaybeScheduleFlushOrCompaction();
     }
+    log_buffer.FlushBufferToLog();
     bg_cv_.SignalAll();
     // IMPORTANT: there should be no code after calling SignalAll. This call may
     // signal the DB destructor that it's OK to proceed with destruction. In
     // that case, all DB variables will be dealloacated and referencing them
     // will cause trouble.
   }
-  log_buffer.FlushBufferToLog();
 }
 
 Status DBImpl::BackgroundCompaction(bool* madeProgress,