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rocksdb/port/win/env_win.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include <algorithm>
#include <deque>
#include <thread>
#include <ctime>
#include <errno.h>
#include <process.h>
#include <io.h>
#include <direct.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "rocksdb/env.h"
#include "rocksdb/slice.h"
#include "port/port.h"
#include "port/dirent.h"
#include "port/win/win_logger.h"
#include "util/random.h"
#include "util/iostats_context_imp.h"
#include "util/rate_limiter.h"
#include "util/sync_point.h"
#include "util/aligned_buffer.h"
#include "util/thread_status_updater.h"
#include "util/thread_status_util.h"
#include <Rpc.h> // For UUID generation
#include <Windows.h>
namespace rocksdb {
std::string GetWindowsErrSz(DWORD err) {
LPSTR lpMsgBuf;
FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL, err,
0, // Default language
reinterpret_cast<LPSTR>(&lpMsgBuf), 0, NULL);
std::string Err = lpMsgBuf;
LocalFree(lpMsgBuf);
return Err;
}
namespace {
const size_t c_OneMB = (1 << 20);
ThreadStatusUpdater* CreateThreadStatusUpdater() {
return new ThreadStatusUpdater();
}
inline Status IOErrorFromWindowsError(const std::string& context, DWORD err) {
return Status::IOError(context, GetWindowsErrSz(err));
}
inline Status IOErrorFromLastWindowsError(const std::string& context) {
return IOErrorFromWindowsError(context, GetLastError());
}
inline Status IOError(const std::string& context, int err_number) {
return Status::IOError(context, strerror(err_number));
}
// TODO(sdong): temp logging. Need to help debugging. Remove it when
// the feature is proved to be stable.
inline void PrintThreadInfo(size_t thread_id, size_t terminatingId) {
fprintf(stdout, "Bg thread %Iu terminates %Iu\n", thread_id, terminatingId);
}
// returns the ID of the current process
inline int current_process_id() { return _getpid(); }
// RAII helpers for HANDLEs
const auto CloseHandleFunc = [](HANDLE h) { ::CloseHandle(h); };
typedef std::unique_ptr<void, decltype(CloseHandleFunc)> UniqueCloseHandlePtr;
// We preserve the original name of this interface to denote the original idea
// behind it.
// All reads happen by a specified offset and pwrite interface does not change
// the position of the file pointer. Judging from the man page and errno it does
// execute
// lseek atomically to return the position of the file back where it was.
// WriteFile() does not
// have this capability. Therefore, for both pread and pwrite the pointer is
// advanced to the next position
// which is fine for writes because they are (should be) sequential.
// Because all the reads/writes happen by the specified offset, the caller in
// theory should not
// rely on the current file offset.
SSIZE_T pwrite(HANDLE hFile, const char* src, size_t numBytes,
uint64_t offset) {
assert(numBytes <= std::numeric_limits<DWORD>::max());
OVERLAPPED overlapped = {0};
ULARGE_INTEGER offsetUnion;
offsetUnion.QuadPart = offset;
overlapped.Offset = offsetUnion.LowPart;
overlapped.OffsetHigh = offsetUnion.HighPart;
SSIZE_T result = 0;
unsigned long bytesWritten = 0;
if (FALSE == WriteFile(hFile, src, static_cast<DWORD>(numBytes), &bytesWritten,
&overlapped)) {
result = -1;
} else {
result = bytesWritten;
}
return result;
}
// See comments for pwrite above
SSIZE_T pread(HANDLE hFile, char* src, size_t numBytes, uint64_t offset) {
assert(numBytes <= std::numeric_limits<DWORD>::max());
OVERLAPPED overlapped = {0};
ULARGE_INTEGER offsetUnion;
offsetUnion.QuadPart = offset;
overlapped.Offset = offsetUnion.LowPart;
overlapped.OffsetHigh = offsetUnion.HighPart;
SSIZE_T result = 0;
unsigned long bytesRead = 0;
if (FALSE == ReadFile(hFile, src, static_cast<DWORD>(numBytes), &bytesRead,
&overlapped)) {
return -1;
} else {
result = bytesRead;
}
return result;
}
// Note the below two do not set errno because they are used only here in this
// file
// on a Windows handle and, therefore, not necessary. Translating GetLastError()
// to errno
// is a sad business
inline int fsync(HANDLE hFile) {
if (!FlushFileBuffers(hFile)) {
return -1;
}
return 0;
}
// SetFileInformationByHandle() is capable of fast pre-allocates.
// However, this does not change the file end position unless the file is
// truncated and the pre-allocated space is not considered filled with zeros.
inline Status fallocate(const std::string& filename, HANDLE hFile,
uint64_t to_size) {
Status status;
FILE_ALLOCATION_INFO alloc_info;
alloc_info.AllocationSize.QuadPart = to_size;
if (!SetFileInformationByHandle(hFile, FileAllocationInfo, &alloc_info,
sizeof(FILE_ALLOCATION_INFO))) {
auto lastError = GetLastError();
status = IOErrorFromWindowsError(
"Failed to pre-allocate space: " + filename, lastError);
}
return status;
}
inline Status ftruncate(const std::string& filename, HANDLE hFile,
uint64_t toSize) {
Status status;
FILE_END_OF_FILE_INFO end_of_file;
end_of_file.EndOfFile.QuadPart = toSize;
if (!SetFileInformationByHandle(hFile, FileEndOfFileInfo, &end_of_file,
sizeof(FILE_END_OF_FILE_INFO))) {
auto lastError = GetLastError();
status = IOErrorFromWindowsError("Failed to Set end of file: " + filename,
lastError);
}
return status;
}
// mmap() based random-access
class WinMmapReadableFile : public RandomAccessFile {
const std::string fileName_;
HANDLE hFile_;
HANDLE hMap_;
const void* mapped_region_;
const size_t length_;
public:
// mapped_region_[0,length-1] contains the mmapped contents of the file.
WinMmapReadableFile(const std::string& fileName, HANDLE hFile, HANDLE hMap,
const void* mapped_region, size_t length)
: fileName_(fileName),
hFile_(hFile),
hMap_(hMap),
mapped_region_(mapped_region),
length_(length) {}
~WinMmapReadableFile() {
BOOL ret = ::UnmapViewOfFile(mapped_region_);
assert(ret);
ret = ::CloseHandle(hMap_);
assert(ret);
ret = ::CloseHandle(hFile_);
assert(ret);
}
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const override {
Status s;
if (offset > length_) {
*result = Slice();
return IOError(fileName_, EINVAL);
} else if (offset + n > length_) {
n = length_ - offset;
}
*result =
Slice(reinterpret_cast<const char*>(mapped_region_) + offset, n);
return s;
}
virtual Status InvalidateCache(size_t offset, size_t length) override {
return Status::OK();
}
};
// We preallocate up to an extra megabyte and use memcpy to append new
// data to the file. This is safe since we either properly close the
// file before reading from it, or for log files, the reading code
// knows enough to skip zero suffixes.
class WinMmapFile : public WritableFile {
private:
const std::string filename_;
HANDLE hFile_;
HANDLE hMap_;
const size_t page_size_; // We flush the mapping view in page_size
// increments. We may decide if this is a memory
// page size or SSD page size
const size_t
allocation_granularity_; // View must start at such a granularity
size_t mapping_size_; // We want file mapping to be of a specific size
// because then the file is expandable
size_t view_size_; // How much memory to map into a view at a time
char* mapped_begin_; // Must begin at the file offset that is aligned with
// allocation_granularity_
char* mapped_end_;
char* dst_; // Where to write next (in range [mapped_begin_,mapped_end_])
char* last_sync_; // Where have we synced up to
uint64_t file_offset_; // Offset of mapped_begin_ in file
// Do we have unsynced writes?
bool pending_sync_;
// Can only truncate or reserve to a sector size aligned if
// used on files that are opened with Unbuffered I/O
Status TruncateFile(uint64_t toSize) {
return ftruncate(filename_, hFile_, toSize);
}
// Can only truncate or reserve to a sector size aligned if
// used on files that are opened with Unbuffered I/O
// Normally it does not present a problem since in memory mapped files
// we do not disable buffering
Status ReserveFileSpace(uint64_t toSize) {
IOSTATS_TIMER_GUARD(allocate_nanos);
return fallocate(filename_, hFile_, toSize);
}
Status UnmapCurrentRegion() {
Status status;
if (mapped_begin_ != nullptr) {
if (!::UnmapViewOfFile(mapped_begin_)) {
status = IOErrorFromWindowsError(
"Failed to unmap file view: " + filename_, GetLastError());
}
// UnmapView automatically sends data to disk but not the metadata
// which is good and provides some equivalent of fdatasync() on Linux
// therefore, we donot need separate flag for metadata
pending_sync_ = false;
mapped_begin_ = nullptr;
mapped_end_ = nullptr;
dst_ = nullptr;
last_sync_ = nullptr;
// Move on to the next portion of the file
file_offset_ += view_size_;
// Increase the amount we map the next time, but capped at 1MB
view_size_ *= 2;
view_size_ = std::min(view_size_, c_OneMB);
}
return status;
}
Status MapNewRegion() {
Status status;
assert(mapped_begin_ == nullptr);
size_t minMappingSize = file_offset_ + view_size_;
// Check if we need to create a new mapping since we want to write beyond
// the current one
// If the mapping view is now too short
// CreateFileMapping will extend the size of the file automatically if the
// mapping size is greater than
// the current length of the file, which reserves the space and makes
// writing faster, except, windows can not map an empty file.
// Thus the first time around we must actually extend the file ourselves
if (hMap_ == NULL || minMappingSize > mapping_size_) {
if (NULL == hMap_) {
// Creating mapping for the first time so reserve the space on disk
status = ReserveFileSpace(minMappingSize);
if (!status.ok()) {
return status;
}
}
if (hMap_) {
// Unmap the previous one
BOOL ret = ::CloseHandle(hMap_);
assert(ret);
hMap_ = NULL;
}
// Calculate the new mapping size which will hopefully reserve space for
// several consecutive sliding views
// Query preallocation block size if set
size_t preallocationBlockSize = 0;
size_t lastAllocatedBlockSize = 0; // Not used
GetPreallocationStatus(&preallocationBlockSize, &lastAllocatedBlockSize);
if (preallocationBlockSize) {
preallocationBlockSize =
Roundup(preallocationBlockSize, allocation_granularity_);
} else {
preallocationBlockSize = 2 * view_size_;
}
mapping_size_ += preallocationBlockSize;
ULARGE_INTEGER mappingSize;
mappingSize.QuadPart = mapping_size_;
hMap_ = CreateFileMappingA(
hFile_,
NULL, // Security attributes
PAGE_READWRITE, // There is not a write only mode for mapping
mappingSize.HighPart, // Enable mapping the whole file but the actual
// amount mapped is determined by MapViewOfFile
mappingSize.LowPart,
NULL); // Mapping name
if (NULL == hMap_) {
return IOErrorFromWindowsError(
"WindowsMmapFile failed to create file mapping for: " + filename_,
GetLastError());
}
}
ULARGE_INTEGER offset;
offset.QuadPart = file_offset_;
// View must begin at the granularity aligned offset
mapped_begin_ = reinterpret_cast<char*>(
MapViewOfFileEx(hMap_, FILE_MAP_WRITE, offset.HighPart, offset.LowPart,
view_size_, NULL));
if (!mapped_begin_) {
status = IOErrorFromWindowsError(
"WindowsMmapFile failed to map file view: " + filename_,
GetLastError());
} else {
mapped_end_ = mapped_begin_ + view_size_;
dst_ = mapped_begin_;
last_sync_ = mapped_begin_;
pending_sync_ = false;
}
return status;
}
public:
WinMmapFile(const std::string& fname, HANDLE hFile, size_t page_size,
size_t allocation_granularity, const EnvOptions& options)
: filename_(fname),
hFile_(hFile),
hMap_(NULL),
page_size_(page_size),
allocation_granularity_(allocation_granularity),
mapping_size_(0),
view_size_(0),
mapped_begin_(nullptr),
mapped_end_(nullptr),
dst_(nullptr),
last_sync_(nullptr),
file_offset_(0),
pending_sync_(false) {
// Allocation granularity must be obtained from GetSystemInfo() and must be
// a power of two.
assert(allocation_granularity > 0);
assert((allocation_granularity & (allocation_granularity - 1)) == 0);
assert(page_size > 0);
assert((page_size & (page_size - 1)) == 0);
// Only for memory mapped writes
assert(options.use_mmap_writes);
// Make sure buffering is not disabled. It is ignored for mapping
// purposes but also imposes restriction on moving file position
// it is not a problem so much with reserving space since it is probably a
// factor
// of allocation_granularity but we also want to truncate the file in
// Close() at
// arbitrary position so we do not have to feel this with zeros.
assert(options.use_os_buffer);
// View size must be both the multiple of allocation_granularity AND the
// page size
if ((allocation_granularity_ % page_size_) == 0) {
view_size_ = 2 * allocation_granularity;
} else if ((page_size_ % allocation_granularity_) == 0) {
view_size_ = 2 * page_size_;
} else {
// we can multiply them together
assert(false);
}
}
~WinMmapFile() {
if (hFile_) {
this->Close();
}
}
virtual Status Append(const Slice& data) override {
const char* src = data.data();
size_t left = data.size();
while (left > 0) {
assert(mapped_begin_ <= dst_);
size_t avail = mapped_end_ - dst_;
if (avail == 0) {
Status s = UnmapCurrentRegion();
if (s.ok()) {
s = MapNewRegion();
}
if (!s.ok()) {
return s;
}
}
size_t n = std::min(left, avail);
memcpy(dst_, src, n);
dst_ += n;
src += n;
left -= n;
pending_sync_ = true;
}
return Status::OK();
}
// Means Close() will properly take care of truncate
// and it does not need any additional information
virtual Status Truncate(uint64_t size) override {
return Status::OK();
}
virtual Status Close() override {
Status s;
assert(NULL != hFile_);
// We truncate to the precise size so no
// uninitialized data at the end. SetEndOfFile
// which we use does not write zeros and it is good.
uint64_t targetSize = GetFileSize();
s = UnmapCurrentRegion();
if (NULL != hMap_) {
BOOL ret = ::CloseHandle(hMap_);
if (!ret && s.ok()) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError(
"Failed to Close mapping for file: " + filename_, lastError);
}
hMap_ = NULL;
}
TruncateFile(targetSize);
BOOL ret = ::CloseHandle(hFile_);
hFile_ = NULL;
if (!ret && s.ok()) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError(
"Failed to close file map handle: " + filename_, lastError);
}
return s;
}
virtual Status Flush() override { return Status::OK(); }
// Flush only data
virtual Status Sync() override {
Status s;
// Some writes occurred since last sync
if (pending_sync_) {
assert(mapped_begin_);
assert(dst_);
assert(dst_ > mapped_begin_);
assert(dst_ < mapped_end_);
size_t page_begin =
TruncateToPageBoundary(page_size_, last_sync_ - mapped_begin_);
size_t page_end =
TruncateToPageBoundary(page_size_, dst_ - mapped_begin_ - 1);
last_sync_ = dst_;
// Flush only the amount of that is a multiple of pages
if (!::FlushViewOfFile(mapped_begin_ + page_begin,
(page_end - page_begin) + page_size_)) {
s = IOErrorFromWindowsError("Failed to FlushViewOfFile: " + filename_,
GetLastError());
}
pending_sync_ = false;
}
return s;
}
/**
* Flush data as well as metadata to stable storage.
*/
virtual Status Fsync() override {
Status s;
// Flush metadata if pending
const bool pending = pending_sync_;
s = Sync();
// Flush metadata
if (s.ok() && pending) {
if (!::FlushFileBuffers(hFile_)) {
s = IOErrorFromWindowsError("Failed to FlushFileBuffers: " + filename_,
GetLastError());
}
}
return s;
}
/**
* Get the size of valid data in the file. This will not match the
* size that is returned from the filesystem because we use mmap
* to extend file by map_size every time.
*/
virtual uint64_t GetFileSize() override {
size_t used = dst_ - mapped_begin_;
return file_offset_ + used;
}
virtual Status InvalidateCache(size_t offset, size_t length) override {
return Status::OK();
}
virtual Status Allocate(uint64_t offset, uint64_t len) override {
return Status::OK();
}
};
class WinSequentialFile : public SequentialFile {
private:
const std::string filename_;
HANDLE file_;
// There is no equivalent of advising away buffered pages as in posix.
// To implement this flag we would need to do unbuffered reads which
// will need to be aligned (not sure there is a guarantee that the buffer
// passed in is aligned).
// Hence we currently ignore this flag. It is used only in a few cases
// which should not be perf critical.
// If perf evaluation finds this to be a problem, we can look into
// implementing this.
bool use_os_buffer_;
public:
WinSequentialFile(const std::string& fname, HANDLE f,
const EnvOptions& options)
: filename_(fname),
file_(f),
use_os_buffer_(options.use_os_buffer) {}
virtual ~WinSequentialFile() {
assert(file_ != INVALID_HANDLE_VALUE);
CloseHandle(file_);
}
virtual Status Read(size_t n, Slice* result, char* scratch) override {
Status s;
size_t r = 0;
// Windows ReadFile API accepts a DWORD.
// While it is possible to read in a loop if n is > UINT_MAX
// it is a highly unlikely case.
if (n > UINT_MAX) {
return IOErrorFromWindowsError(filename_, ERROR_INVALID_PARAMETER);
}
DWORD bytesToRead = static_cast<DWORD>(n); //cast is safe due to the check above
DWORD bytesRead = 0;
BOOL ret = ReadFile(file_, scratch, bytesToRead, &bytesRead, NULL);
if (ret == TRUE) {
r = bytesRead;
} else {
return IOErrorFromWindowsError(filename_, GetLastError());
}
*result = Slice(scratch, r);
return s;
}
virtual Status Skip(uint64_t n) override {
// Can't handle more than signed max as SetFilePointerEx accepts a signed 64-bit
// integer. As such it is a highly unlikley case to have n so large.
if (n > _I64_MAX) {
return IOErrorFromWindowsError(filename_, ERROR_INVALID_PARAMETER);
}
LARGE_INTEGER li;
li.QuadPart = static_cast<int64_t>(n); //cast is safe due to the check above
BOOL ret = SetFilePointerEx(file_, li, NULL, FILE_CURRENT);
if (ret == FALSE) {
return IOErrorFromWindowsError(filename_, GetLastError());
}
return Status::OK();
}
virtual Status InvalidateCache(size_t offset, size_t length) override {
return Status::OK();
}
};
// pread() based random-access
class WinRandomAccessFile : public RandomAccessFile {
const std::string filename_;
HANDLE hFile_;
const bool use_os_buffer_;
bool read_ahead_;
const size_t compaction_readahead_size_;
const size_t random_access_max_buffer_size_;
mutable std::mutex buffer_mut_;
mutable AlignedBuffer buffer_;
mutable uint64_t
buffered_start_; // file offset set that is currently buffered
/*
* The function reads a requested amount of bytes into the specified aligned
* buffer Upon success the function sets the length of the buffer to the
* amount of bytes actually read even though it might be less than actually
* requested. It then copies the amount of bytes requested by the user (left)
* to the user supplied buffer (dest) and reduces left by the amount of bytes
* copied to the user buffer
*
* @user_offset [in] - offset on disk where the read was requested by the user
* @first_page_start [in] - actual page aligned disk offset that we want to
* read from
* @bytes_to_read [in] - total amount of bytes that will be read from disk
* which is generally greater or equal to the amount
* that the user has requested due to the
* either alignment requirements or read_ahead in
* effect.
* @left [in/out] total amount of bytes that needs to be copied to the user
* buffer. It is reduced by the amount of bytes that actually
* copied
* @buffer - buffer to use
* @dest - user supplied buffer
*/
SSIZE_T ReadIntoBuffer(uint64_t user_offset, uint64_t first_page_start,
size_t bytes_to_read, size_t& left,
AlignedBuffer& buffer, char* dest) const {
assert(buffer.CurrentSize() == 0);
assert(buffer.Capacity() >= bytes_to_read);
SSIZE_T read =
pread(hFile_, buffer.Destination(), bytes_to_read, first_page_start);
if (read > 0) {
buffer.Size(read);
// Let's figure out how much we read from the users standpoint
if ((first_page_start + buffer.CurrentSize()) > user_offset) {
assert(first_page_start <= user_offset);
size_t buffer_offset = user_offset - first_page_start;
read = buffer.Read(dest, buffer_offset, left);
} else {
read = 0;
}
left -= read;
}
return read;
}
SSIZE_T ReadIntoOneShotBuffer(uint64_t user_offset, uint64_t first_page_start,
size_t bytes_to_read, size_t& left,
char* dest) const {
AlignedBuffer bigBuffer;
bigBuffer.Alignment(buffer_.Alignment());
bigBuffer.AllocateNewBuffer(bytes_to_read);
return ReadIntoBuffer(user_offset, first_page_start, bytes_to_read, left,
bigBuffer, dest);
}
SSIZE_T ReadIntoInstanceBuffer(uint64_t user_offset,
uint64_t first_page_start,
size_t bytes_to_read, size_t& left,
char* dest) const {
SSIZE_T read = ReadIntoBuffer(user_offset, first_page_start, bytes_to_read,
left, buffer_, dest);
if (read > 0) {
buffered_start_ = first_page_start;
}
return read;
}
void CalculateReadParameters(uint64_t offset, size_t bytes_requested,
size_t& actual_bytes_toread,
uint64_t& first_page_start) const {
const size_t alignment = buffer_.Alignment();
first_page_start = TruncateToPageBoundary(alignment, offset);
const uint64_t last_page_start =
TruncateToPageBoundary(alignment, offset + bytes_requested - 1);
actual_bytes_toread = (last_page_start - first_page_start) + alignment;
}
public:
WinRandomAccessFile(const std::string& fname, HANDLE hFile, size_t alignment,
const EnvOptions& options)
: filename_(fname),
hFile_(hFile),
use_os_buffer_(options.use_os_buffer),
read_ahead_(false),
compaction_readahead_size_(options.compaction_readahead_size),
random_access_max_buffer_size_(options.random_access_max_buffer_size),
buffer_(),
buffered_start_(0) {
assert(!options.use_mmap_reads);
// Unbuffered access, use internal buffer for reads
if (!use_os_buffer_) {
// Do not allocate the buffer either until the first request or
// until there is a call to allocate a read-ahead buffer
buffer_.Alignment(alignment);
}
}
virtual ~WinRandomAccessFile() {
if (hFile_ != NULL && hFile_ != INVALID_HANDLE_VALUE) {
::CloseHandle(hFile_);
}
}
virtual void EnableReadAhead() override { this->Hint(SEQUENTIAL); }
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const override {
Status s;
SSIZE_T r = -1;
size_t left = n;
char* dest = scratch;
if (n == 0) {
*result = Slice(scratch, 0);
return s;
}
// When in unbuffered mode we need to do the following changes:
// - use our own aligned buffer
// - always read at the offset of that is a multiple of alignment
if (!use_os_buffer_) {
uint64_t first_page_start = 0;
size_t actual_bytes_toread = 0;
size_t bytes_requested = left;
if (!read_ahead_ && random_access_max_buffer_size_ == 0) {
CalculateReadParameters(offset, bytes_requested, actual_bytes_toread,
first_page_start);
assert(actual_bytes_toread > 0);
r = ReadIntoOneShotBuffer(offset, first_page_start,
actual_bytes_toread, left, dest);
} else {
std::unique_lock<std::mutex> lock(buffer_mut_);
// Let's see if at least some of the requested data is already
// in the buffer
if (offset >= buffered_start_ &&
offset < (buffered_start_ + buffer_.CurrentSize())) {
size_t buffer_offset = offset - buffered_start_;
r = buffer_.Read(dest, buffer_offset, left);
assert(r >= 0);
left -= size_t(r);
offset += r;
dest += r;
}
// Still some left or none was buffered
if (left > 0) {
// Figure out the start/end offset for reading and amount to read
bytes_requested = left;
if (read_ahead_ && bytes_requested < compaction_readahead_size_) {
bytes_requested = compaction_readahead_size_;
}
CalculateReadParameters(offset, bytes_requested, actual_bytes_toread,
first_page_start);
assert(actual_bytes_toread > 0);
if (buffer_.Capacity() < actual_bytes_toread) {
// If we are in read-ahead mode or the requested size
// exceeds max buffer size then use one-shot
// big buffer otherwise reallocate main buffer
if (read_ahead_ ||
(actual_bytes_toread > random_access_max_buffer_size_)) {
// Unlock the mutex since we are not using instance buffer
lock.unlock();
r = ReadIntoOneShotBuffer(offset, first_page_start,
actual_bytes_toread, left, dest);
}
else {
buffer_.AllocateNewBuffer(actual_bytes_toread);
r = ReadIntoInstanceBuffer(offset, first_page_start,
actual_bytes_toread, left, dest);
}
}
else {
buffer_.Clear();
r = ReadIntoInstanceBuffer(offset, first_page_start,
actual_bytes_toread, left, dest);
}
}
}
} else {
r = pread(hFile_, scratch, left, offset);
if (r > 0) {
left -= r;
}
}
*result = Slice(scratch, (r < 0) ? 0 : n - left);
if (r < 0) {
s = IOErrorFromLastWindowsError(filename_);
}
return s;
}
virtual bool ShouldForwardRawRequest() const override {
return true;
}
virtual void Hint(AccessPattern pattern) override {
if (pattern == SEQUENTIAL && !use_os_buffer_ &&
compaction_readahead_size_ > 0) {
std::lock_guard<std::mutex> lg(buffer_mut_);
if (!read_ahead_) {
read_ahead_ = true;
// This would allocate read-ahead size + 2 alignments
// - one for memory alignment which added implicitly by AlignedBuffer
// - We add one more alignment because we will read one alignment more
// from disk
buffer_.AllocateNewBuffer(compaction_readahead_size_ +
buffer_.Alignment());
}
}
}
virtual Status InvalidateCache(size_t offset, size_t length) override {
return Status::OK();
}
};
// This is a sequential write class. It has been mimicked (as others) after
// the original Posix class. We add support for unbuffered I/O on windows as
// well
// we utilize the original buffer as an alignment buffer to write directly to
// file with no buffering.
// No buffering requires that the provided buffer is aligned to the physical
// sector size (SSD page size) and
// that all SetFilePointer() operations to occur with such an alignment.
// We thus always write in sector/page size increments to the drive and leave
// the tail for the next write OR for Close() at which point we pad with zeros.
// No padding is required for
// buffered access.
class WinWritableFile : public WritableFile {
private:
const std::string filename_;
HANDLE hFile_;
const bool use_os_buffer_; // Used to indicate unbuffered access, the file
const uint64_t alignment_;
// must be opened as unbuffered if false
uint64_t filesize_; // How much data is actually written disk
uint64_t reservedsize_; // how far we have reserved space
public:
WinWritableFile(const std::string& fname, HANDLE hFile, size_t alignment,
size_t capacity, const EnvOptions& options)
: filename_(fname),
hFile_(hFile),
use_os_buffer_(options.use_os_buffer),
alignment_(alignment),
filesize_(0),
reservedsize_(0) {
assert(!options.use_mmap_writes);
}
~WinWritableFile() {
if (NULL != hFile_ && INVALID_HANDLE_VALUE != hFile_) {
WinWritableFile::Close();
}
}
// Indicates if the class makes use of unbuffered I/O
virtual bool UseOSBuffer() const override {
return use_os_buffer_;
}
virtual size_t GetRequiredBufferAlignment() const override {
return alignment_;
}
virtual Status Append(const Slice& data) override {
// Used for buffered access ONLY
assert(use_os_buffer_);
assert(data.size() < std::numeric_limits<DWORD>::max());
Status s;
DWORD bytesWritten = 0;
if (!WriteFile(hFile_, data.data(),
static_cast<DWORD>(data.size()), &bytesWritten, NULL)) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError(
"Failed to WriteFile: " + filename_,
lastError);
} else {
assert(size_t(bytesWritten) == data.size());
filesize_ += data.size();
}
return s;
}
virtual Status PositionedAppend(const Slice& data, uint64_t offset) override {
Status s;
SSIZE_T ret = pwrite(hFile_, data.data(), data.size(), offset);
// Error break
if (ret < 0) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError(
"Failed to pwrite for: " + filename_, lastError);
} else {
// With positional write it is not clear at all
// if this actually extends the filesize
assert(size_t(ret) == data.size());
filesize_ += data.size();
}
return s;
}
// Need to implement this so the file is truncated correctly
// when buffered and unbuffered mode
virtual Status Truncate(uint64_t size) override {
Status s = ftruncate(filename_, hFile_, size);
if (s.ok()) {
filesize_ = size;
}
return s;
}
virtual Status Close() override {
Status s;
assert(INVALID_HANDLE_VALUE != hFile_);
if (fsync(hFile_) < 0) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("fsync failed at Close() for: " + filename_,
lastError);
}
if (FALSE == ::CloseHandle(hFile_)) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("CloseHandle failed for: " + filename_,
lastError);
}
hFile_ = INVALID_HANDLE_VALUE;
return s;
}
// write out the cached data to the OS cache
// This is now taken care of the WritableFileWriter
virtual Status Flush() override {
return Status::OK();
}
virtual Status Sync() override {
Status s;
// Calls flush buffers
if (fsync(hFile_) < 0) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("fsync failed at Sync() for: " + filename_,
lastError);
}
return s;
}
virtual Status Fsync() override { return Sync(); }
virtual uint64_t GetFileSize() override {
// Double accounting now here with WritableFileWriter
// and this size will be wrong when unbuffered access is used
// but tests implement their own writable files and do not use WritableFileWrapper
// so we need to squeeze a square peg through
// a round hole here.
return filesize_;
}
virtual Status Allocate(uint64_t offset, uint64_t len) override {
Status status;
TEST_KILL_RANDOM("WinWritableFile::Allocate", rocksdb_kill_odds);
// Make sure that we reserve an aligned amount of space
// since the reservation block size is driven outside so we want
// to check if we are ok with reservation here
size_t spaceToReserve = Roundup(offset + len, alignment_);
// Nothing to do
if (spaceToReserve <= reservedsize_) {
return status;
}
IOSTATS_TIMER_GUARD(allocate_nanos);
status = fallocate(filename_, hFile_, spaceToReserve);
if (status.ok()) {
reservedsize_ = spaceToReserve;
}
return status;
}
};
class WinDirectory : public Directory {
public:
WinDirectory() {}
virtual Status Fsync() override { return Status::OK(); }
};
class WinFileLock : public FileLock {
public:
explicit WinFileLock(HANDLE hFile) : hFile_(hFile) {
assert(hFile != NULL);
assert(hFile != INVALID_HANDLE_VALUE);
}
~WinFileLock() {
BOOL ret = ::CloseHandle(hFile_);
assert(ret);
}
private:
HANDLE hFile_;
};
namespace {
void WinthreadCall(const char* label, std::error_code result) {
if (0 != result.value()) {
fprintf(stderr, "pthread %s: %s\n", label, strerror(result.value()));
abort();
}
}
}
class WinEnv : public Env {
public:
WinEnv();
virtual ~WinEnv() {
for (auto& th : threads_to_join_) {
th.join();
}
threads_to_join_.clear();
for (auto& thpool : thread_pools_) {
thpool.JoinAllThreads();
}
// All threads must be joined before the deletion of
// thread_status_updater_.
delete thread_status_updater_;
}
virtual Status DeleteFile(const std::string& fname) override {
Status result;
if (_unlink(fname.c_str())) {
result = IOError("Failed to delete: " + fname, errno);
}
return result;
}
Status GetCurrentTime(int64_t* unix_time) override {
time_t time = std::time(nullptr);
if (time == (time_t)(-1)) {
return Status::NotSupported("Failed to get time");
}
*unix_time = time;
return Status::OK();
}
virtual Status NewSequentialFile(const std::string& fname,
std::unique_ptr<SequentialFile>* result,
const EnvOptions& options) override {
Status s;
result->reset();
// Corruption test needs to rename and delete files of these kind
// while they are still open with another handle. For that reason we
// allow share_write and delete(allows rename).
HANDLE hFile = INVALID_HANDLE_VALUE;
{
IOSTATS_TIMER_GUARD(open_nanos);
hFile = CreateFileA(
fname.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
OPEN_EXISTING, // Original fopen mode is "rb"
FILE_ATTRIBUTE_NORMAL, NULL);
}
if (INVALID_HANDLE_VALUE == hFile) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("Failed to open NewSequentialFile" + fname,
lastError);
} else {
result->reset(new WinSequentialFile(fname, hFile, options));
}
return s;
}
virtual Status NewRandomAccessFile(const std::string& fname,
std::unique_ptr<RandomAccessFile>* result,
const EnvOptions& options) override {
result->reset();
Status s;
// Open the file for read-only random access
// Random access is to disable read-ahead as the system reads too much data
DWORD fileFlags = FILE_ATTRIBUTE_READONLY;
if (!options.use_os_buffer && !options.use_mmap_reads) {
fileFlags |= FILE_FLAG_NO_BUFFERING;
} else {
fileFlags |= FILE_FLAG_RANDOM_ACCESS;
}
/// Shared access is necessary for corruption test to pass
// almost all tests would work with a possible exception of fault_injection
HANDLE hFile = 0;
{
IOSTATS_TIMER_GUARD(open_nanos);
hFile =
CreateFileA(fname.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
NULL, OPEN_EXISTING, fileFlags, NULL);
}
if (INVALID_HANDLE_VALUE == hFile) {
auto lastError = GetLastError();
return IOErrorFromWindowsError(
"NewRandomAccessFile failed to Create/Open: " + fname, lastError);
}
UniqueCloseHandlePtr fileGuard(hFile, CloseHandleFunc);
// CAUTION! This will map the entire file into the process address space
if (options.use_mmap_reads && sizeof(void*) >= 8) {
// Use mmap when virtual address-space is plentiful.
uint64_t fileSize;
s = GetFileSize(fname, &fileSize);
if (s.ok()) {
// Will not map empty files
if (fileSize == 0) {
return IOError(
"NewRandomAccessFile failed to map empty file: " + fname, EINVAL);
}
HANDLE hMap = CreateFileMappingA(hFile, NULL, PAGE_READONLY,
0, // Whole file at its present length
0,
NULL); // Mapping name
if (!hMap) {
auto lastError = GetLastError();
return IOErrorFromWindowsError(
"Failed to create file mapping for NewRandomAccessFile: " + fname,
lastError);
}
UniqueCloseHandlePtr mapGuard(hMap, CloseHandleFunc);
const void* mapped_region =
MapViewOfFileEx(hMap, FILE_MAP_READ,
0, // High DWORD of access start
0, // Low DWORD
fileSize,
NULL); // Let the OS choose the mapping
if (!mapped_region) {
auto lastError = GetLastError();
return IOErrorFromWindowsError(
"Failed to MapViewOfFile for NewRandomAccessFile: " + fname,
lastError);
}
result->reset(new WinMmapReadableFile(fname, hFile, hMap, mapped_region,
fileSize));
mapGuard.release();
fileGuard.release();
}
} else {
result->reset(new WinRandomAccessFile(fname, hFile, page_size_, options));
fileGuard.release();
}
return s;
}
virtual Status NewWritableFile(const std::string& fname,
std::unique_ptr<WritableFile>* result,
const EnvOptions& options) override {
const size_t c_BufferCapacity = 64 * 1024;
EnvOptions local_options(options);
result->reset();
Status s;
DWORD fileFlags = FILE_ATTRIBUTE_NORMAL;
if (!local_options.use_os_buffer && !local_options.use_mmap_writes) {
fileFlags = FILE_FLAG_NO_BUFFERING;
}
// Desired access. We are want to write only here but if we want to memory
// map
// the file then there is no write only mode so we have to create it
// Read/Write
// However, MapViewOfFile specifies only Write only
DWORD desired_access = GENERIC_WRITE;
DWORD shared_mode = FILE_SHARE_READ;
if (local_options.use_mmap_writes) {
desired_access |= GENERIC_READ;
} else {
// Adding this solely for tests to pass (fault_injection_test,
// wal_manager_test).
shared_mode |= (FILE_SHARE_WRITE | FILE_SHARE_DELETE);
}
HANDLE hFile = 0;
{
IOSTATS_TIMER_GUARD(open_nanos);
hFile = CreateFileA(
fname.c_str(),
desired_access, // Access desired
shared_mode,
NULL, // Security attributes
CREATE_ALWAYS, // Posix env says O_CREAT | O_RDWR | O_TRUNC
fileFlags, // Flags
NULL); // Template File
}
if (INVALID_HANDLE_VALUE == hFile) {
auto lastError = GetLastError();
return IOErrorFromWindowsError(
"Failed to create a NewWriteableFile: " + fname, lastError);
}
if (options.use_mmap_writes) {
// We usually do not use mmmapping on SSD and thus we pass memory
// page_size
result->reset(new WinMmapFile(fname, hFile, page_size_,
allocation_granularity_, local_options));
} else {
// Here we want the buffer allocation to be aligned by the SSD page size
// and to be a multiple of it
result->reset(new WinWritableFile(fname, hFile, page_size_,
c_BufferCapacity, local_options));
}
return s;
}
virtual Status NewDirectory(const std::string& name,
std::unique_ptr<Directory>* result) override {
Status s;
// Must be nullptr on failure
result->reset();
// Must fail if directory does not exist
if (!DirExists(name)) {
s = IOError("Directory does not exist: " + name, EEXIST);
} else {
IOSTATS_TIMER_GUARD(open_nanos);
result->reset(new WinDirectory);
}
return s;
}
virtual Status FileExists(const std::string& fname) override {
// F_OK == 0
const int F_OK_ = 0;
return _access(fname.c_str(), F_OK_) == 0 ? Status::OK()
: Status::NotFound();
}
virtual Status GetChildren(const std::string& dir,
std::vector<std::string>* result) override {
std::vector<std::string> output;
Status status;
auto CloseDir = [](DIR* p) { closedir(p); };
std::unique_ptr<DIR, decltype(CloseDir)> dirp(opendir(dir.c_str()),
CloseDir);
if (!dirp) {
status = IOError(dir, errno);
} else {
if (result->capacity() > 0) {
output.reserve(result->capacity());
}
struct dirent* ent = readdir(dirp.get());
while (ent) {
output.push_back(ent->d_name);
ent = readdir(dirp.get());
}
}
output.swap(*result);
return status;
}
virtual Status CreateDir(const std::string& name) override {
Status result;
if (_mkdir(name.c_str()) != 0) {
auto code = errno;
result = IOError("Failed to create dir: " + name, code);
}
return result;
}
virtual Status CreateDirIfMissing(const std::string& name) override {
Status result;
if (DirExists(name)) {
return result;
}
if (_mkdir(name.c_str()) != 0) {
if (errno == EEXIST) {
result =
Status::IOError("`" + name + "' exists but is not a directory");
} else {
auto code = errno;
result = IOError("Failed to create dir: " + name, code);
}
}
return result;
}
virtual Status DeleteDir(const std::string& name) override {
Status result;
if (_rmdir(name.c_str()) != 0) {
auto code = errno;
result = IOError("Failed to remove dir: " + name, code);
}
return result;
}
virtual Status GetFileSize(const std::string& fname,
uint64_t* size) override {
Status s;
WIN32_FILE_ATTRIBUTE_DATA attrs;
if (GetFileAttributesExA(fname.c_str(), GetFileExInfoStandard, &attrs)) {
ULARGE_INTEGER file_size;
file_size.HighPart = attrs.nFileSizeHigh;
file_size.LowPart = attrs.nFileSizeLow;
*size = file_size.QuadPart;
} else {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("Can not get size for: " + fname, lastError);
}
return s;
}
static inline uint64_t FileTimeToUnixTime(const FILETIME& ftTime) {
const uint64_t c_FileTimePerSecond = 10000000U;
// UNIX epoch starts on 1970-01-01T00:00:00Z
// Windows FILETIME starts on 1601-01-01T00:00:00Z
// Therefore, we need to subtract the below number of seconds from
// the seconds that we obtain from FILETIME with an obvious loss of
// precision
const uint64_t c_SecondBeforeUnixEpoch = 11644473600U;
ULARGE_INTEGER li;
li.HighPart = ftTime.dwHighDateTime;
li.LowPart = ftTime.dwLowDateTime;
uint64_t result =
(li.QuadPart / c_FileTimePerSecond) - c_SecondBeforeUnixEpoch;
return result;
}
virtual Status GetFileModificationTime(const std::string& fname,
uint64_t* file_mtime) override {
Status s;
WIN32_FILE_ATTRIBUTE_DATA attrs;
if (GetFileAttributesExA(fname.c_str(), GetFileExInfoStandard, &attrs)) {
*file_mtime = FileTimeToUnixTime(attrs.ftLastWriteTime);
} else {
auto lastError = GetLastError();
s = IOErrorFromWindowsError(
"Can not get file modification time for: " + fname, lastError);
*file_mtime = 0;
}
return s;
}
virtual Status RenameFile(const std::string& src,
const std::string& target) override {
Status result;
// rename() is not capable of replacing the existing file as on Linux
// so use OS API directly
if (!MoveFileExA(src.c_str(), target.c_str(), MOVEFILE_REPLACE_EXISTING)) {
DWORD lastError = GetLastError();
std::string text("Failed to rename: ");
text.append(src).append(" to: ").append(target);
result = IOErrorFromWindowsError(text, lastError);
}
return result;
}
virtual Status LinkFile(const std::string& src,
const std::string& target) override {
Status result;
if (!CreateHardLinkA(target.c_str(), src.c_str(), NULL)) {
DWORD lastError = GetLastError();
std::string text("Failed to link: ");
text.append(src).append(" to: ").append(target);
result = IOErrorFromWindowsError(text, lastError);
}
return result;
}
virtual Status LockFile(const std::string& lockFname,
FileLock** lock) override {
assert(lock != nullptr);
*lock = NULL;
Status result;
// No-sharing, this is a LOCK file
const DWORD ExclusiveAccessON = 0;
// Obtain exclusive access to the LOCK file
// Previously, instead of NORMAL attr we set DELETE on close and that worked
// well except with fault_injection test that insists on deleting it.
HANDLE hFile = 0;
{
IOSTATS_TIMER_GUARD(open_nanos);
hFile = CreateFileA(lockFname.c_str(), (GENERIC_READ | GENERIC_WRITE),
ExclusiveAccessON, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL);
}
if (INVALID_HANDLE_VALUE == hFile) {
auto lastError = GetLastError();
result = IOErrorFromWindowsError(
"Failed to create lock file: " + lockFname, lastError);
} else {
*lock = new WinFileLock(hFile);
}
return result;
}
virtual Status UnlockFile(FileLock* lock) override {
Status result;
assert(lock != nullptr);
delete lock;
return result;
}
virtual void Schedule(void (*function)(void*), void* arg, Priority pri = LOW,
void* tag = nullptr,
void (*unschedFunction)(void* arg) = 0) override;
virtual int UnSchedule(void* arg, Priority pri) override;
virtual void StartThread(void (*function)(void* arg), void* arg) override;
virtual void WaitForJoin() override;
virtual unsigned int GetThreadPoolQueueLen(Priority pri = LOW) const override;
virtual Status GetTestDirectory(std::string* result) override {
std::string output;
const char* env = getenv("TEST_TMPDIR");
if (env && env[0] != '\0') {
output = env;
CreateDir(output);
} else {
env = getenv("TMP");
if (env && env[0] != '\0') {
output = env;
} else {
output = "c:\\tmp";
}
CreateDir(output);
}
output.append("\\testrocksdb-");
output.append(std::to_string(_getpid()));
CreateDir(output);
output.swap(*result);
return Status::OK();
}
virtual Status GetThreadList(
std::vector<ThreadStatus>* thread_list) override {
assert(thread_status_updater_);
return thread_status_updater_->GetThreadList(thread_list);
}
static uint64_t gettid() {
uint64_t thread_id = GetCurrentThreadId();
return thread_id;
}
virtual uint64_t GetThreadID() const override { return gettid(); }
virtual Status NewLogger(const std::string& fname,
std::shared_ptr<Logger>* result) override {
Status s;
result->reset();
HANDLE hFile = 0;
{
IOSTATS_TIMER_GUARD(open_nanos);
hFile = CreateFileA(
fname.c_str(), GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_DELETE, // In RocksDb log files are
// renamed and deleted before
// they are closed. This enables
// doing so.
NULL,
CREATE_ALWAYS, // Original fopen mode is "w"
FILE_ATTRIBUTE_NORMAL, NULL);
}
if (INVALID_HANDLE_VALUE == hFile) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("Failed to open LogFile" + fname, lastError);
} else {
{
// With log files we want to set the true creation time as of now
// because the system
// for some reason caches the attributes of the previous file that just
// been renamed from
// this name so auto_roll_logger_test fails
FILETIME ft;
GetSystemTimeAsFileTime(&ft);
// Set creation, last access and last write time to the same value
SetFileTime(hFile, &ft, &ft, &ft);
}
result->reset(new WinLogger(&WinEnv::gettid, this, hFile));
}
return s;
}
virtual uint64_t NowMicros() override {
// all std::chrono clocks on windows proved to return
// values that may repeat that is not good enough for some uses.
const int64_t c_UnixEpochStartTicks = 116444736000000000i64;
const int64_t c_FtToMicroSec = 10;
// This interface needs to return system time and not
// just any microseconds because it is often used as an argument
// to TimedWait() on condition variable
FILETIME ftSystemTime;
GetSystemTimePreciseAsFileTime(&ftSystemTime);
LARGE_INTEGER li;
li.LowPart = ftSystemTime.dwLowDateTime;
li.HighPart = ftSystemTime.dwHighDateTime;
// Subtract unix epoch start
li.QuadPart -= c_UnixEpochStartTicks;
// Convert to microsecs
li.QuadPart /= c_FtToMicroSec;
return li.QuadPart;
}
virtual uint64_t NowNanos() override {
// all std::chrono clocks on windows have the same resolution that is only
// good enough for microseconds but not nanoseconds
// On Windows 8 and Windows 2012 Server
// GetSystemTimePreciseAsFileTime(&current_time) can be used
LARGE_INTEGER li;
QueryPerformanceCounter(&li);
// Convert to nanoseconds first to avoid loss of precision
// and divide by frequency
li.QuadPart *= std::nano::den;
li.QuadPart /= perf_counter_frequency_;
return li.QuadPart;
}
virtual void SleepForMicroseconds(int micros) override {
std::this_thread::sleep_for(std::chrono::microseconds(micros));
}
virtual Status GetHostName(char* name, uint64_t len) override {
Status s;
DWORD nSize =
static_cast<DWORD>(std::min<uint64_t>(len,
std::numeric_limits<DWORD>::max()));
if (!::GetComputerNameA(name, &nSize)) {
auto lastError = GetLastError();
s = IOErrorFromWindowsError("GetHostName", lastError);
} else {
name[nSize] = 0;
}
return s;
}
virtual Status GetCurrTime(int64_t* unix_time) {
Status s;
time_t ret = time(nullptr);
if (ret == (time_t)-1) {
*unix_time = 0;
s = IOError("GetCurrTime", errno);
} else {
*unix_time = (int64_t)ret;
}
return s;
}
virtual Status GetAbsolutePath(const std::string& db_path,
std::string* output_path) override {
// Check if we already have an absolute path
// that starts with non dot and has a semicolon in it
if ((!db_path.empty() && (db_path[0] == '/' || db_path[0] == '\\')) ||
(db_path.size() > 2 && db_path[0] != '.' &&
((db_path[1] == ':' && db_path[2] == '\\') ||
(db_path[1] == ':' && db_path[2] == '/')))) {
*output_path = db_path;
return Status::OK();
}
std::string result;
result.resize(_MAX_PATH);
char* ret = _getcwd(&result[0], _MAX_PATH);
if (ret == nullptr) {
return Status::IOError("Failed to get current working directory",
strerror(errno));
}
result.resize(strlen(result.data()));
result.swap(*output_path);
return Status::OK();
}
// Allow increasing the number of worker threads.
virtual void SetBackgroundThreads(int num, Priority pri) override {
assert(pri >= Priority::LOW && pri <= Priority::HIGH);
thread_pools_[pri].SetBackgroundThreads(num);
}
virtual void IncBackgroundThreadsIfNeeded(int num, Priority pri) override {
assert(pri >= Priority::LOW && pri <= Priority::HIGH);
thread_pools_[pri].IncBackgroundThreadsIfNeeded(num);
}
virtual std::string TimeToString(uint64_t secondsSince1970) override {
std::string result;
const time_t seconds = secondsSince1970;
const int maxsize = 64;
struct tm t;
errno_t ret = localtime_s(&t, &seconds);
if (ret) {
result = std::to_string(seconds);
} else {
result.resize(maxsize);
char* p = &result[0];
int len = snprintf(p, maxsize, "%04d/%02d/%02d-%02d:%02d:%02d ",
t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour,
t.tm_min, t.tm_sec);
assert(len > 0);
result.resize(len);
}
return result;
}
EnvOptions OptimizeForLogWrite(const EnvOptions& env_options,
const DBOptions& db_options) const override {
EnvOptions optimized = env_options;
optimized.use_mmap_writes = false;
optimized.bytes_per_sync = db_options.wal_bytes_per_sync;
optimized.use_os_buffer =
true; // This is because we flush only whole pages on unbuffered io and
// the last records are not guaranteed to be flushed.
// TODO(icanadi) it's faster if fallocate_with_keep_size is false, but it
// breaks TransactionLogIteratorStallAtLastRecord unit test. Fix the unit
// test and make this false
optimized.fallocate_with_keep_size = true;
return optimized;
}
EnvOptions OptimizeForManifestWrite(
const EnvOptions& env_options) const override {
EnvOptions optimized = env_options;
optimized.use_mmap_writes = false;
optimized.use_os_buffer = true;
optimized.fallocate_with_keep_size = true;
return optimized;
}
private:
// Returns true iff the named directory exists and is a directory.
virtual bool DirExists(const std::string& dname) {
WIN32_FILE_ATTRIBUTE_DATA attrs;
if (GetFileAttributesExA(dname.c_str(), GetFileExInfoStandard, &attrs)) {
return 0 != (attrs.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
}
return false;
}
bool SupportsFastAllocate(const std::string& /* path */) { return false; }
class ThreadPool {
public:
ThreadPool()
: total_threads_limit_(1),
bgthreads_(0),
queue_(),
queue_len_(0U),
exit_all_threads_(false),
low_io_priority_(false),
env_(nullptr) {}
~ThreadPool() { assert(bgthreads_.size() == 0U); }
void JoinAllThreads() {
{
std::lock_guard<std::mutex> lock(mu_);
assert(!exit_all_threads_);
exit_all_threads_ = true;
bgsignal_.notify_all();
}
for (std::thread& th : bgthreads_) {
th.join();
}
// Subject to assert in the __dtor
bgthreads_.clear();
}
void SetHostEnv(Env* env) { env_ = env; }
// Return true if there is at least one thread needs to terminate.
bool HasExcessiveThread() const {
return bgthreads_.size() > total_threads_limit_;
}
// Return true iff the current thread is the excessive thread to terminate.
// Always terminate the running thread that is added last, even if there are
// more than one thread to terminate.
bool IsLastExcessiveThread(size_t thread_id) const {
return HasExcessiveThread() && thread_id == bgthreads_.size() - 1;
}
// Is one of the threads to terminate.
bool IsExcessiveThread(size_t thread_id) const {
return thread_id >= total_threads_limit_;
}
// Return the thread priority.
// This would allow its member-thread to know its priority.
Env::Priority GetThreadPriority() { return priority_; }
// Set the thread priority.
void SetThreadPriority(Env::Priority priority) { priority_ = priority; }
void BGThread(size_t thread_id) {
while (true) {
// Wait until there is an item that is ready to run
std::unique_lock<std::mutex> uniqueLock(mu_);
// Stop waiting if the thread needs to do work or needs to terminate.
while (!exit_all_threads_ && !IsLastExcessiveThread(thread_id) &&
(queue_.empty() || IsExcessiveThread(thread_id))) {
bgsignal_.wait(uniqueLock);
}
if (exit_all_threads_) {
// mechanism to let BG threads exit safely
uniqueLock.unlock();
break;
}
if (IsLastExcessiveThread(thread_id)) {
// Current thread is the last generated one and is excessive.
// We always terminate excessive thread in the reverse order of
// generation time.
std::thread& terminating_thread = bgthreads_.back();
auto tid = terminating_thread.get_id();
// Ensure that that this thread is ours
assert(tid == std::this_thread::get_id());
terminating_thread.detach();
bgthreads_.pop_back();
if (HasExcessiveThread()) {
// There is still at least more excessive thread to terminate.
WakeUpAllThreads();
}
uniqueLock.unlock();
PrintThreadInfo(thread_id, gettid());
break;
}
void (*function)(void*) = queue_.front().function;
void* arg = queue_.front().arg;
queue_.pop_front();
queue_len_.store(queue_.size(), std::memory_order_relaxed);
uniqueLock.unlock();
(*function)(arg);
}
}
// Helper struct for passing arguments when creating threads.
struct BGThreadMetadata {
ThreadPool* thread_pool_;
size_t thread_id_; // Thread count in the thread.
BGThreadMetadata(ThreadPool* thread_pool, size_t thread_id)
: thread_pool_(thread_pool), thread_id_(thread_id) {}
};
static void* BGThreadWrapper(void* arg) {
std::unique_ptr<BGThreadMetadata> meta(
reinterpret_cast<BGThreadMetadata*>(arg));
size_t thread_id = meta->thread_id_;
ThreadPool* tp = meta->thread_pool_;
#if ROCKSDB_USING_THREAD_STATUS
// for thread-status
ThreadStatusUtil::RegisterThread(
tp->env_, (tp->GetThreadPriority() == Env::Priority::HIGH
? ThreadStatus::HIGH_PRIORITY
: ThreadStatus::LOW_PRIORITY));
#endif
tp->BGThread(thread_id);
#if ROCKSDB_USING_THREAD_STATUS
ThreadStatusUtil::UnregisterThread();
#endif
return nullptr;
}
void WakeUpAllThreads() { bgsignal_.notify_all(); }
void SetBackgroundThreadsInternal(size_t num, bool allow_reduce) {
std::lock_guard<std::mutex> lg(mu_);
if (exit_all_threads_) {
return;
}
if (num > total_threads_limit_ ||
(num < total_threads_limit_ && allow_reduce)) {
total_threads_limit_ = std::max(size_t(1), num);
WakeUpAllThreads();
StartBGThreads();
}
assert(total_threads_limit_ > 0);
}
void IncBackgroundThreadsIfNeeded(int num) {
SetBackgroundThreadsInternal(num, false);
}
void SetBackgroundThreads(int num) {
SetBackgroundThreadsInternal(num, true);
}
void StartBGThreads() {
// Start background thread if necessary
while (bgthreads_.size() < total_threads_limit_) {
std::thread p_t(&ThreadPool::BGThreadWrapper,
new BGThreadMetadata(this, bgthreads_.size()));
bgthreads_.push_back(std::move(p_t));
}
}
void Schedule(void (*function)(void* arg1), void* arg, void* tag,
void (*unschedFunction)(void* arg)) {
std::lock_guard<std::mutex> lg(mu_);
if (exit_all_threads_) {
return;
}
StartBGThreads();
// Add to priority queue
queue_.push_back(BGItem());
queue_.back().function = function;
queue_.back().arg = arg;
queue_.back().tag = tag;
queue_.back().unschedFunction = unschedFunction;
queue_len_.store(queue_.size(), std::memory_order_relaxed);
if (!HasExcessiveThread()) {
// Wake up at least one waiting thread.
bgsignal_.notify_one();
} else {
// Need to wake up all threads to make sure the one woken
// up is not the one to terminate.
WakeUpAllThreads();
}
}
int UnSchedule(void* arg) {
int count = 0;
std::lock_guard<std::mutex> lg(mu_);
// Remove from priority queue
BGQueue::iterator it = queue_.begin();
while (it != queue_.end()) {
if (arg == (*it).tag) {
void (*unschedFunction)(void*) = (*it).unschedFunction;
void* arg1 = (*it).arg;
if (unschedFunction != nullptr) {
(*unschedFunction)(arg1);
}
it = queue_.erase(it);
count++;
} else {
++it;
}
}
queue_len_.store(queue_.size(), std::memory_order_relaxed);
return count;
}
unsigned int GetQueueLen() const {
return static_cast<unsigned int>(
queue_len_.load(std::memory_order_relaxed));
}
private:
// Entry per Schedule() call
struct BGItem {
void* arg;
void (*function)(void*);
void* tag;
void (*unschedFunction)(void*);
};
typedef std::deque<BGItem> BGQueue;
std::mutex mu_;
std::condition_variable bgsignal_;
size_t total_threads_limit_;
std::vector<std::thread> bgthreads_;
BGQueue queue_;
std::atomic_size_t queue_len_; // Queue length. Used for stats reporting
bool exit_all_threads_;
bool low_io_priority_;
Env::Priority priority_;
Env* env_;
};
bool checkedDiskForMmap_;
bool forceMmapOff; // do we override Env options?
size_t page_size_;
size_t allocation_granularity_;
uint64_t perf_counter_frequency_;
std::vector<ThreadPool> thread_pools_;
mutable std::mutex mu_;
std::vector<std::thread> threads_to_join_;
};
WinEnv::WinEnv()
: checkedDiskForMmap_(false),
forceMmapOff(false),
page_size_(4 * 1012),
allocation_granularity_(page_size_),
perf_counter_frequency_(0),
thread_pools_(Priority::TOTAL) {
SYSTEM_INFO sinfo;
GetSystemInfo(&sinfo);
page_size_ = sinfo.dwPageSize;
allocation_granularity_ = sinfo.dwAllocationGranularity;
{
LARGE_INTEGER qpf;
BOOL ret = QueryPerformanceFrequency(&qpf);
assert(ret == TRUE);
perf_counter_frequency_ = qpf.QuadPart;
}
for (int pool_id = 0; pool_id < Env::Priority::TOTAL; ++pool_id) {
thread_pools_[pool_id].SetThreadPriority(
static_cast<Env::Priority>(pool_id));
// This allows later initializing the thread-local-env of each thread.
thread_pools_[pool_id].SetHostEnv(this);
}
// Protected member of the base class
thread_status_updater_ = CreateThreadStatusUpdater();
}
void WinEnv::Schedule(void (*function)(void*), void* arg, Priority pri,
void* tag, void (*unschedFunction)(void* arg)) {
assert(pri >= Priority::LOW && pri <= Priority::HIGH);
thread_pools_[pri].Schedule(function, arg, tag, unschedFunction);
}
int WinEnv::UnSchedule(void* arg, Priority pri) {
return thread_pools_[pri].UnSchedule(arg);
}
unsigned int WinEnv::GetThreadPoolQueueLen(Priority pri) const {
assert(pri >= Priority::LOW && pri <= Priority::HIGH);
return thread_pools_[pri].GetQueueLen();
}
namespace {
struct StartThreadState {
void (*user_function)(void*);
void* arg;
};
}
static void* StartThreadWrapper(void* arg) {
std::unique_ptr<StartThreadState> state(
reinterpret_cast<StartThreadState*>(arg));
state->user_function(state->arg);
return nullptr;
}
void WinEnv::StartThread(void (*function)(void* arg), void* arg) {
StartThreadState* state = new StartThreadState;
state->user_function = function;
state->arg = arg;
try {
std::thread th(&StartThreadWrapper, state);
std::lock_guard<std::mutex> lg(mu_);
threads_to_join_.push_back(std::move(th));
} catch (const std::system_error& ex) {
WinthreadCall("start thread", ex.code());
}
}
void WinEnv::WaitForJoin() {
for (auto& th : threads_to_join_) {
th.join();
}
threads_to_join_.clear();
}
} // namespace
std::string Env::GenerateUniqueId() {
std::string result;
UUID uuid;
UuidCreateSequential(&uuid);
RPC_CSTR rpc_str;
auto status = UuidToStringA(&uuid, &rpc_str);
assert(status == RPC_S_OK);
result = reinterpret_cast<char*>(rpc_str);
status = RpcStringFreeA(&rpc_str);
assert(status == RPC_S_OK);
return result;
}
// We choose to create this on the heap and using std::once for the following
// reasons
// 1) Currently available MS compiler does not implement atomic C++11
// initialization of
// function local statics
// 2) We choose not to destroy the env because joining the threads from the
// system loader
// which destroys the statics (same as from DLLMain) creates a system loader
// dead-lock.
// in this manner any remaining threads are terminated OK.
namespace {
std::once_flag winenv_once_flag;
Env* envptr;
};
Env* Env::Default() {
std::call_once(winenv_once_flag, []() { envptr = new WinEnv(); });
return envptr;
}
} // namespace rocksdb