From b4cd51d847bb41bb80df999393b2acac4f67219d Mon Sep 17 00:00:00 2001
From: Akanksha Mahajan <akankshamahajan@fb.com>
Date: Tue, 20 Oct 2020 09:11:50 -0700
Subject: [PATCH] Fix for stress test failure (#7574)

Summary:
Ignore read error in 'FilePrefetchBuffer::TryReadFromCache' as status is ignored
and  bool value is returned. Return error if prefetch fails in
'PrefetchTail' as we have planned to return Prefetch failures to users.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7574

Test Plan:
make check -j64,
python -u tools/db_crashtest.py blackbox

Reviewed By: zhichao-cao

Differential Revision: D24408825

Pulled By: akankshamahajan15

fbshipit-source-id: feebda771415998253fbe54632f13e6e75b7a243
---
 file/file_prefetch_buffer.cc                  | 3 +++
 table/block_based/block_based_table_reader.cc | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/file/file_prefetch_buffer.cc b/file/file_prefetch_buffer.cc
index d813a7bb3..ce98177be 100644
--- a/file/file_prefetch_buffer.cc
+++ b/file/file_prefetch_buffer.cc
@@ -134,6 +134,9 @@ bool FilePrefetchBuffer::TryReadFromCache(const IOOptions& opts,
                      for_compaction);
       }
       if (!s.ok()) {
+#ifndef NDEBUG
+        IGNORE_STATUS_IF_ERROR(s);
+#endif
         return false;
       }
       readahead_size_ = std::min(max_readahead_size_, readahead_size_ * 2);
diff --git a/table/block_based/block_based_table_reader.cc b/table/block_based/block_based_table_reader.cc
index e92fdff7e..75abd8788 100644
--- a/table/block_based/block_based_table_reader.cc
+++ b/table/block_based/block_based_table_reader.cc
@@ -612,6 +612,10 @@ Status BlockBasedTable::Open(
     s = PrefetchTail(ro, file.get(), file_size, force_direct_prefetch,
                      tail_prefetch_stats, prefetch_all, preload_all,
                      &prefetch_buffer);
+    // Return error in prefetch path to users.
+    if (!s.ok()) {
+      return s;
+    }
   } else {
     // Should not prefetch for mmap mode.
     prefetch_buffer.reset(new FilePrefetchBuffer(