From a618a16f44f4390a1591ca898f4cd54474a30192 Mon Sep 17 00:00:00 2001
From: Marcin Dlugajczyk <dlugajczykmarcin@gmail.com>
Date: Fri, 17 Feb 2017 10:47:35 -0800
Subject: [PATCH] New subcode for IOError to detect the ESTALE errno

Summary:
I'd like to propose a patch to expose a new IOError type with subcode kStaleFile to allow to detect when ESTALE error is returned. This allows the rocksdb consumers to handle this error separately from other IOErrors.

I've also added a missing string representation for the kDeadlock subcode, I believe calling ToString() on Status object with that subcode would result in an out of band access in the msgs array,

Please let me know if you have any questions or would like me to make any changes to this pull request.
Closes https://github.com/facebook/rocksdb/pull/1748

Differential Revision: D4387675

Pulled By: IslamAbdelRahman

fbshipit-source-id: 67feb13
---
 include/rocksdb/status.h |  1 +
 util/io_posix.h          | 11 ++++++++---
 util/status_message.cc   |  4 +++-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/rocksdb/status.h b/include/rocksdb/status.h
index 078d5c1b4..40f3eecd2 100644
--- a/include/rocksdb/status.h
+++ b/include/rocksdb/status.h
@@ -70,6 +70,7 @@ class Status {
     kLockLimit = 3,
     kNoSpace = 4,
     kDeadlock = 5,
+    kStaleFile = 6,
     kMaxSubCode
   };
 
diff --git a/util/io_posix.h b/util/io_posix.h
index 3bf155a82..5fb8f85c4 100644
--- a/util/io_posix.h
+++ b/util/io_posix.h
@@ -26,9 +26,14 @@
 namespace rocksdb {
 
 static Status IOError(const std::string& context, int err_number) {
-  return (err_number == ENOSPC) ?
-      Status::NoSpace(context, strerror(err_number)) :
-      Status::IOError(context, strerror(err_number));
+  switch (err_number) {
+  case ENOSPC:
+    return Status::NoSpace(context, strerror(err_number));
+  case ESTALE:
+    return Status::IOError(Status::kStaleFile);
+  default:
+    return Status::IOError(context, strerror(err_number));
+  }
 }
 
 class PosixHelper {
diff --git a/util/status_message.cc b/util/status_message.cc
index 94ae65128..01956f26c 100644
--- a/util/status_message.cc
+++ b/util/status_message.cc
@@ -12,7 +12,9 @@ const char* Status::msgs[] = {
     "Timeout Acquiring Mutex",                            // kMutexTimeout
     "Timeout waiting to lock key",                        // kLockTimeout
     "Failed to acquire lock due to max_num_locks limit",  // kLockLimit
-    "No space left on device"                             // kNoSpace
+    "No space left on device",                            // kNoSpace
+    "Deadlock",                                           // kDeadlock
+    "Stale file handle"                                   // kStaleFile
 };
 
 }  // namespace rocksdb