Summary:
I am seeing crashes during backups. The stack trace points back to `WritableFileWriter` creation inside `BackupEngineImpl::CopyOrCreateFile`. I believe the issue is that we are calling `writable_file_->GetRequiredBufferAlignment()` with a `null` `writable_file`.
https://github.com/facebook/rocksdb/blob/v10.2.1/utilities/backup/backup_engine.cc#L2396-L2397https://github.com/facebook/rocksdb/blob/v10.2.1/file/writable_file_writer.h#L210
Here's how I think the flow is:
```cpp
io_s = dst_env->GetFileSystem()->NewWritableFile(dst, dst_file_options,
&dst_file, nullptr);
// say there was some issue and dst_file is nullptr
// evaluates to false
if (io_s.ok() && !src.empty()) {
// we don't go down this branch
auto src_file_options = FileOptions(src_env_options);
src_file_options.temperature = *src_temperature;
io_s = src_env->GetFileSystem()->NewSequentialFile(src, src_file_options,
&src_file, nullptr);
}
// say this evaluates to true
if (io_s.IsPathNotFound() && *src_temperature != Temperature::kUnknown) {
// Retry without temperature hint in case the FileSystem is strict with
// non-kUnknown temperature option
io_s = src_env->GetFileSystem()->NewSequentialFile(
src, FileOptions(src_env_options), &src_file, nullptr);
}
// this is now from the NewSequentialFile call, not NewWritableFile
if (!io_s.ok()) {
return io_s;
}
// dst_file is still nullptr
```
If the first `NewWritableFile` fails and `IsPathNotFound
Tests: existing unit tests
Pull Request resolved: https://github.com/facebook/rocksdb/pull/13734
Reviewed By: pdillinger
Differential Revision: D77390694
Pulled By: archang19
fbshipit-source-id: 865a3a646079ae2349a3b6f25e53ae85df8e4985
7183422b17