Pass IOStatus to write path and set retryable IO Error as hard error …

…in BG jobs (#6487)

Summary:
In the current code base, we use Status to get and store the returned status from the call. Specifically, for IO related functions, the current Status cannot reflect the IO Error details such as error scope, error retryable attribute, and others. With the implementation of facebook/rocksdb#5761, we have the new Wrapper for IO, which returns IOStatus instead of Status. However, the IOStatus is purged at the lower level of write path and transferred to Status.

The first job of this PR is to pass the IOStatus to the write path (flush, WAL write, and Compaction). The second job is to identify the Retryable IO Error as HardError, and set the bg_error_ as HardError. In this case, the DB Instance becomes read only. User is informed of the Status and need to take actions to deal with it (e.g., call db->Resume()).
Pull Request resolved: facebook/rocksdb#6487

Test Plan: Added the testing case to error_handler_fs_test. Pass make asan_check

Reviewed By: anand1976

Differential Revision: D20685017

Pulled By: zhichao-cao

fbshipit-source-id: ff85f042896243abcd6ef37877834e26f36b6eb0
Signed-off-by: Changlong Chen <levisonchen@live.cn>

env/composite_env_wrapper.h

@@ -20,22 +20,6 @@ namespace ROCKSDB_NAMESPACE {
 // Options::env only, whereas in the latter case, the user will specify
 // Options::env and Options::file_system.
 
-inline IOStatus status_to_io_status(Status&& status) {
-  if (status.ok()) {
-    // Fast path
-    return IOStatus::OK();
-  } else {
-    const char* state = status.getState();
-    if (state) {
-      return IOStatus(status.code(), status.subcode(),
-                      Slice(state, strlen(status.getState()) + 1),
-                      Slice());
-    } else {
-      return IOStatus(status.code(), status.subcode());
-    }
-  }
-}
-
 class CompositeSequentialFileWrapper : public SequentialFile {
  public:
   explicit CompositeSequentialFileWrapper(

env/file_system.cc

@@ -83,12 +83,31 @@ FileOptions FileSystem::OptimizeForCompactionTableRead(
   return optimized_file_options;
 }
 
-Status ReadFileToString(FileSystem* fs, const std::string& fname,
-                        std::string* data) {
+IOStatus WriteStringToFile(FileSystem* fs, const Slice& data,
+                           const std::string& fname, bool should_sync) {
+  std::unique_ptr<FSWritableFile> file;
+  EnvOptions soptions;
+  IOStatus s = fs->NewWritableFile(fname, soptions, &file, nullptr);
+  if (!s.ok()) {
+    return s;
+  }
+  s = file->Append(data, IOOptions(), nullptr);
+  if (s.ok() && should_sync) {
+    s = file->Sync(IOOptions(), nullptr);
+  }
+  if (!s.ok()) {
+    fs->DeleteFile(fname, IOOptions(), nullptr);
+  }
+  return s;
+}
+
+IOStatus ReadFileToString(FileSystem* fs, const std::string& fname,
+                          std::string* data) {
   FileOptions soptions;
   data->clear();
   std::unique_ptr<FSSequentialFile> file;
-  Status s = fs->NewSequentialFile(fname, soptions, &file, nullptr);
+  IOStatus s = status_to_io_status(
+      fs->NewSequentialFile(fname, soptions, &file, nullptr));
   if (!s.ok()) {
     return s;
   }