From 7aa105e1a34e6e52b1e0de16d9d659a2af26fa0a Mon Sep 17 00:00:00 2001 From: "Wladimir J. van der Laan" Date: Wed, 4 Nov 2015 17:44:30 +0100 Subject: [PATCH] leveldb: Win32WritableFile without memory mapping Use a straightforward Win32WritableFile for writing files, equivalent to PosixWritableFile in posix_env.cc, but using only the Win32 API. The goal is to solve leveldb corruption issues on windows after crashes, which are frequently reported. --- util/env_win.cc | 236 ++++++++---------------------------------------- 1 file changed, 39 insertions(+), 197 deletions(-) diff --git a/util/env_win.cc b/util/env_win.cc index ef2ecae830662..e11a96b791871 100644 --- a/util/env_win.cc +++ b/util/env_win.cc @@ -103,39 +103,20 @@ class Win32RandomAccessFile : public RandomAccessFile DISALLOW_COPY_AND_ASSIGN(Win32RandomAccessFile); }; -class Win32MapFile : public WritableFile +class Win32WritableFile : public WritableFile { public: - Win32MapFile(const std::string& fname); + Win32WritableFile(const std::string& fname); + ~Win32WritableFile(); - ~Win32MapFile(); virtual Status Append(const Slice& data); virtual Status Close(); virtual Status Flush(); virtual Status Sync(); BOOL isEnable(); private: - std::string _filename; - HANDLE _hFile; - size_t _page_size; - size_t _map_size; // How much extra memory to map at a time - char* _base; // The mapped region - HANDLE _base_handle; - char* _limit; // Limit of the mapped region - char* _dst; // Where to write next (in range [base_,limit_]) - char* _last_sync; // Where have we synced up to - uint64_t _file_offset; // Offset of base_ in file - //LARGE_INTEGER file_offset_; - // Have we done an munmap of unsynced data? - bool _pending_sync; - - // Roundup x to a multiple of y - static size_t _Roundup(size_t x, size_t y); - size_t _TruncateToPageBoundary(size_t s); - bool _UnmapCurrentRegion(); - bool _MapNewRegion(); - DISALLOW_COPY_AND_ASSIGN(Win32MapFile); - BOOL _Init(LPCWSTR Path); + std::string filename_; + ::HANDLE _hFile; }; class Win32FileLock : public FileLock @@ -442,202 +423,63 @@ void Win32RandomAccessFile::_CleanUp() } } -size_t Win32MapFile::_Roundup( size_t x, size_t y ) +Win32WritableFile::Win32WritableFile(const std::string& fname) + : filename_(fname) { - return ((x + y - 1) / y) * y; + std::wstring path; + ToWidePath(fname, path); + DWORD Flag = PathFileExistsW(path.c_str()) ? OPEN_EXISTING : CREATE_ALWAYS; + _hFile = CreateFileW(path.c_str(), + GENERIC_READ | GENERIC_WRITE, + FILE_SHARE_READ|FILE_SHARE_DELETE|FILE_SHARE_WRITE, + NULL, + Flag, + FILE_ATTRIBUTE_NORMAL, + NULL); + // CreateFileW returns INVALID_HANDLE_VALUE in case of error, always check isEnable() before use } -size_t Win32MapFile::_TruncateToPageBoundary( size_t s ) +Win32WritableFile::~Win32WritableFile() { - s -= (s & (_page_size - 1)); - assert((s % _page_size) == 0); - return s; + if (_hFile != INVALID_HANDLE_VALUE) + Close(); } -bool Win32MapFile::_UnmapCurrentRegion() +Status Win32WritableFile::Append(const Slice& data) { - bool result = true; - if (_base != NULL) { - if (_last_sync < _limit) { - // Defer syncing this data until next Sync() call, if any - _pending_sync = true; - } - if (!UnmapViewOfFile(_base) || !CloseHandle(_base_handle)) - result = false; - _file_offset += _limit - _base; - _base = NULL; - _base_handle = NULL; - _limit = NULL; - _last_sync = NULL; - _dst = NULL; - // Increase the amount we map the next time, but capped at 1MB - if (_map_size < (1<<20)) { - _map_size *= 2; - } + DWORD r = 0; + if (!WriteFile(_hFile, data.data(), data.size(), &r, NULL) || r != data.size()) { + return Status::IOError("Win32WritableFile.Append::WriteFile: "+filename_, Win32::GetLastErrSz()); } - return result; -} - -bool Win32MapFile::_MapNewRegion() -{ - assert(_base == NULL); - //LONG newSizeHigh = (LONG)((file_offset_ + map_size_) >> 32); - //LONG newSizeLow = (LONG)((file_offset_ + map_size_) & 0xFFFFFFFF); - DWORD off_hi = (DWORD)(_file_offset >> 32); - DWORD off_lo = (DWORD)(_file_offset & 0xFFFFFFFF); - LARGE_INTEGER newSize; - newSize.QuadPart = _file_offset + _map_size; - SetFilePointerEx(_hFile, newSize, NULL, FILE_BEGIN); - SetEndOfFile(_hFile); - - _base_handle = CreateFileMappingA( - _hFile, - NULL, - PAGE_READWRITE, - 0, - 0, - 0); - if (_base_handle != NULL) { - _base = (char*) MapViewOfFile(_base_handle, - FILE_MAP_ALL_ACCESS, - off_hi, - off_lo, - _map_size); - if (_base != NULL) { - _limit = _base + _map_size; - _dst = _base; - _last_sync = _base; - return true; - } - } - return false; + return Status::OK(); } -Win32MapFile::Win32MapFile( const std::string& fname) : - _filename(fname), - _hFile(NULL), - _page_size(Win32::g_PageSize), - _map_size(_Roundup(65536, Win32::g_PageSize)), - _base(NULL), - _base_handle(NULL), - _limit(NULL), - _dst(NULL), - _last_sync(NULL), - _file_offset(0), - _pending_sync(false) +Status Win32WritableFile::Close() { - std::wstring path; - ToWidePath(fname, path); - _Init(path.c_str()); - assert((Win32::g_PageSize & (Win32::g_PageSize - 1)) == 0); -} - -Status Win32MapFile::Append( const Slice& data ) -{ - const char* src = data.data(); - size_t left = data.size(); - Status s; - while (left > 0) { - assert(_base <= _dst); - assert(_dst <= _limit); - size_t avail = _limit - _dst; - if (avail == 0) { - if (!_UnmapCurrentRegion() || - !_MapNewRegion()) { - return Status::IOError("WinMmapFile.Append::UnmapCurrentRegion or MapNewRegion: ", Win32::GetLastErrSz()); - } - } - size_t n = (left <= avail) ? left : avail; - memcpy(_dst, src, n); - _dst += n; - src += n; - left -= n; - } - return s; -} - -Status Win32MapFile::Close() -{ - Status s; - size_t unused = _limit - _dst; - if (!_UnmapCurrentRegion()) { - s = Status::IOError("WinMmapFile.Close::UnmapCurrentRegion: ",Win32::GetLastErrSz()); - } else if (unused > 0) { - // Trim the extra space at the end of the file - LARGE_INTEGER newSize; - newSize.QuadPart = _file_offset - unused; - if (!SetFilePointerEx(_hFile, newSize, NULL, FILE_BEGIN)) { - s = Status::IOError("WinMmapFile.Close::SetFilePointer: ",Win32::GetLastErrSz()); - } else - SetEndOfFile(_hFile); - } if (!CloseHandle(_hFile)) { - if (s.ok()) { - s = Status::IOError("WinMmapFile.Close::CloseHandle: ", Win32::GetLastErrSz()); - } + return Status::IOError("Win32WritableFile.Close::CloseHandle: "+filename_, Win32::GetLastErrSz()); } _hFile = INVALID_HANDLE_VALUE; - _base = NULL; - _base_handle = NULL; - _limit = NULL; - - return s; -} - -Status Win32MapFile::Sync() -{ - Status s; - if (_pending_sync) { - // Some unmapped data was not synced - _pending_sync = false; - if (!FlushFileBuffers(_hFile)) { - s = Status::IOError("WinMmapFile.Sync::FlushFileBuffers: ",Win32::GetLastErrSz()); - } - } - if (_dst > _last_sync) { - // Find the beginnings of the pages that contain the first and last - // bytes to be synced. - size_t p1 = _TruncateToPageBoundary(_last_sync - _base); - size_t p2 = _TruncateToPageBoundary(_dst - _base - 1); - _last_sync = _dst; - if (!FlushViewOfFile(_base + p1, p2 - p1 + _page_size)) { - s = Status::IOError("WinMmapFile.Sync::FlushViewOfFile: ",Win32::GetLastErrSz()); - } - } - return s; + return Status::OK(); } -Status Win32MapFile::Flush() +Status Win32WritableFile::Flush() { + // Nothing to do here, there are no application-side buffers return Status::OK(); } -Win32MapFile::~Win32MapFile() +Status Win32WritableFile::Sync() { - if (_hFile != INVALID_HANDLE_VALUE) { - Win32MapFile::Close(); + if (!FlushFileBuffers(_hFile)) { + return Status::IOError("Win32WritableFile.Sync::FlushFileBuffers "+filename_, Win32::GetLastErrSz()); } + return Status::OK(); } -BOOL Win32MapFile::_Init( LPCWSTR Path ) -{ - DWORD Flag = PathFileExistsW(Path) ? OPEN_EXISTING : CREATE_ALWAYS; - _hFile = CreateFileW(Path, - GENERIC_READ | GENERIC_WRITE, - FILE_SHARE_READ|FILE_SHARE_DELETE|FILE_SHARE_WRITE, - NULL, - Flag, - FILE_ATTRIBUTE_NORMAL, - NULL); - if(!_hFile || _hFile == INVALID_HANDLE_VALUE) - return FALSE; - else - return TRUE; -} - -BOOL Win32MapFile::isEnable() +BOOL Win32WritableFile::isEnable() { - return _hFile ? TRUE : FALSE; + return _hFile != INVALID_HANDLE_VALUE; } Win32FileLock::Win32FileLock( const std::string& fname ) : @@ -981,7 +823,7 @@ Status Win32Env::NewLogger( const std::string& fname, Logger** result ) { Status sRet; std::string path = fname; - Win32MapFile* pMapFile = new Win32MapFile(ModifyPath(path)); + Win32WritableFile* pMapFile = new Win32WritableFile(ModifyPath(path)); if(!pMapFile->isEnable()){ delete pMapFile; *result = NULL; @@ -995,7 +837,7 @@ Status Win32Env::NewWritableFile( const std::string& fname, WritableFile** resul { Status sRet; std::string path = fname; - Win32MapFile* pFile = new Win32MapFile(ModifyPath(path)); + Win32WritableFile* pFile = new Win32WritableFile(ModifyPath(path)); if(!pFile->isEnable()){ *result = NULL; sRet = Status::IOError(fname,Win32::GetLastErrSz());