Windows ReFS bug

.md

Summary

FSCTL_QUERY_FILE_REGIONS stuck on sparse file on ReFS(v2) with 64KB cluster size.

Affect

• Windows Server 2025 (26100.3194)

Not affect

How to stuck

Do Format E: /FS:ReFS /A:64K /Q.
Run below code.

test.cpp

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winioctl.h>

int main()
{
	HANDLE h = CreateFileW(LR"(E:\test.dat)", GENERIC_READ | GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, 0, nullptr);
	ULONG _;
	DeviceIoControl(h, FSCTL_SET_SPARSE, nullptr, 0, nullptr, 0, &_, nullptr);
	FILE_END_OF_FILE_INFO eof = { {.QuadPart = 16LL * 1024 * 1024 * 1024 } };
	SetFileInformationByHandle(h, FileEndOfFileInfo, &eof, sizeof eof);
	FILE_REGION_OUTPUT file_region_output;
	DeviceIoControl(h, FSCTL_QUERY_FILE_REGIONS, nullptr, 0, &file_region_output, sizeof file_region_output, &_, nullptr);
}