rocksdb/file/sst_file_manager_impl.cc
anand76 beb86addeb Fix race condition in SstFileManagerImpl error recovery code (#9435)
Summary:
There is a race in SstFileManagerImpl between the ClearError() function
and CancelErrorRecovery(). The race can cause ClearError() to deref the
file system pointer after it has been freed. This is likely to occur
during process shutdown, when the order of destruction of the
DB/Env/FileSystem and SstFileManagerImpl is not deterministic.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9435

Test Plan:
Reproduce the crash in a TSAN build by introducing sleeps in the code, and verify with
the fix.

Reviewed By: siying

Differential Revision: D33774696

Pulled By: anand1976

fbshipit-source-id: 643d3da31b8d2ee6d9b6db5d33327e0053ce3b83
2022-01-25 23:22:58 -08:00

528 lines
18 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "file/sst_file_manager_impl.h"
#include <cinttypes>
#include <vector>
#include "db/db_impl/db_impl.h"
#include "logging/logging.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/sst_file_manager.h"
#include "test_util/sync_point.h"
#include "util/mutexlock.h"
namespace ROCKSDB_NAMESPACE {
#ifndef ROCKSDB_LITE
SstFileManagerImpl::SstFileManagerImpl(
const std::shared_ptr<SystemClock>& clock,
const std::shared_ptr<FileSystem>& fs,
const std::shared_ptr<Logger>& logger, int64_t rate_bytes_per_sec,
double max_trash_db_ratio, uint64_t bytes_max_delete_chunk)
: clock_(clock),
fs_(fs),
logger_(logger),
total_files_size_(0),
compaction_buffer_size_(0),
cur_compactions_reserved_size_(0),
max_allowed_space_(0),
delete_scheduler_(clock_.get(), fs_.get(), rate_bytes_per_sec,
logger.get(), this, max_trash_db_ratio,
bytes_max_delete_chunk),
cv_(&mu_),
closing_(false),
bg_thread_(nullptr),
reserved_disk_buffer_(0),
free_space_trigger_(0),
cur_instance_(nullptr) {}
SstFileManagerImpl::~SstFileManagerImpl() {
Close();
bg_err_.PermitUncheckedError();
}
void SstFileManagerImpl::Close() {
{
MutexLock l(&mu_);
if (closing_) {
return;
}
closing_ = true;
cv_.SignalAll();
}
if (bg_thread_) {
bg_thread_->join();
}
}
Status SstFileManagerImpl::OnAddFile(const std::string& file_path) {
uint64_t file_size;
Status s = fs_->GetFileSize(file_path, IOOptions(), &file_size, nullptr);
if (s.ok()) {
MutexLock l(&mu_);
OnAddFileImpl(file_path, file_size);
}
TEST_SYNC_POINT_CALLBACK("SstFileManagerImpl::OnAddFile",
const_cast<std::string*>(&file_path));
return s;
}
Status SstFileManagerImpl::OnAddFile(const std::string& file_path,
uint64_t file_size) {
MutexLock l(&mu_);
OnAddFileImpl(file_path, file_size);
TEST_SYNC_POINT_CALLBACK("SstFileManagerImpl::OnAddFile",
const_cast<std::string*>(&file_path));
return Status::OK();
}
Status SstFileManagerImpl::OnDeleteFile(const std::string& file_path) {
{
MutexLock l(&mu_);
OnDeleteFileImpl(file_path);
}
TEST_SYNC_POINT_CALLBACK("SstFileManagerImpl::OnDeleteFile",
const_cast<std::string*>(&file_path));
return Status::OK();
}
void SstFileManagerImpl::OnCompactionCompletion(Compaction* c) {
MutexLock l(&mu_);
uint64_t size_added_by_compaction = 0;
for (size_t i = 0; i < c->num_input_levels(); i++) {
for (size_t j = 0; j < c->num_input_files(i); j++) {
FileMetaData* filemeta = c->input(i, j);
size_added_by_compaction += filemeta->fd.GetFileSize();
}
}
cur_compactions_reserved_size_ -= size_added_by_compaction;
}
Status SstFileManagerImpl::OnMoveFile(const std::string& old_path,
const std::string& new_path,
uint64_t* file_size) {
{
MutexLock l(&mu_);
if (file_size != nullptr) {
*file_size = tracked_files_[old_path];
}
OnAddFileImpl(new_path, tracked_files_[old_path]);
OnDeleteFileImpl(old_path);
}
TEST_SYNC_POINT("SstFileManagerImpl::OnMoveFile");
return Status::OK();
}
void SstFileManagerImpl::SetMaxAllowedSpaceUsage(uint64_t max_allowed_space) {
MutexLock l(&mu_);
max_allowed_space_ = max_allowed_space;
}
void SstFileManagerImpl::SetCompactionBufferSize(
uint64_t compaction_buffer_size) {
MutexLock l(&mu_);
compaction_buffer_size_ = compaction_buffer_size;
}
bool SstFileManagerImpl::IsMaxAllowedSpaceReached() {
MutexLock l(&mu_);
if (max_allowed_space_ <= 0) {
return false;
}
return total_files_size_ >= max_allowed_space_;
}
bool SstFileManagerImpl::IsMaxAllowedSpaceReachedIncludingCompactions() {
MutexLock l(&mu_);
if (max_allowed_space_ <= 0) {
return false;
}
return total_files_size_ + cur_compactions_reserved_size_ >=
max_allowed_space_;
}
bool SstFileManagerImpl::EnoughRoomForCompaction(
ColumnFamilyData* cfd, const std::vector<CompactionInputFiles>& inputs,
const Status& bg_error) {
MutexLock l(&mu_);
uint64_t size_added_by_compaction = 0;
// First check if we even have the space to do the compaction
for (size_t i = 0; i < inputs.size(); i++) {
for (size_t j = 0; j < inputs[i].size(); j++) {
FileMetaData* filemeta = inputs[i][j];
size_added_by_compaction += filemeta->fd.GetFileSize();
}
}
// Update cur_compactions_reserved_size_ so concurrent compaction
// don't max out space
size_t needed_headroom =
cur_compactions_reserved_size_ + size_added_by_compaction +
compaction_buffer_size_;
if (max_allowed_space_ != 0 &&
(needed_headroom + total_files_size_ > max_allowed_space_)) {
return false;
}
// Implement more aggressive checks only if this DB instance has already
// seen a NoSpace() error. This is tin order to contain a single potentially
// misbehaving DB instance and prevent it from slowing down compactions of
// other DB instances
if (bg_error.IsNoSpace() && CheckFreeSpace()) {
auto fn =
TableFileName(cfd->ioptions()->cf_paths, inputs[0][0]->fd.GetNumber(),
inputs[0][0]->fd.GetPathId());
uint64_t free_space = 0;
Status s = fs_->GetFreeSpace(fn, IOOptions(), &free_space, nullptr);
s.PermitUncheckedError(); // TODO: Check the status
// needed_headroom is based on current size reserved by compactions,
// minus any files created by running compactions as they would count
// against the reserved size. If user didn't specify any compaction
// buffer, add reserved_disk_buffer_ that's calculated by default so the
// compaction doesn't end up leaving nothing for logs and flush SSTs
if (compaction_buffer_size_ == 0) {
needed_headroom += reserved_disk_buffer_;
}
if (free_space < needed_headroom + size_added_by_compaction) {
// We hit the condition of not enough disk space
ROCKS_LOG_ERROR(logger_,
"free space [%" PRIu64
" bytes] is less than "
"needed headroom [%" ROCKSDB_PRIszt " bytes]\n",
free_space, needed_headroom);
return false;
}
}
cur_compactions_reserved_size_ += size_added_by_compaction;
// Take a snapshot of cur_compactions_reserved_size_ for when we encounter
// a NoSpace error.
free_space_trigger_ = cur_compactions_reserved_size_;
return true;
}
uint64_t SstFileManagerImpl::GetCompactionsReservedSize() {
MutexLock l(&mu_);
return cur_compactions_reserved_size_;
}
uint64_t SstFileManagerImpl::GetTotalSize() {
MutexLock l(&mu_);
return total_files_size_;
}
std::unordered_map<std::string, uint64_t>
SstFileManagerImpl::GetTrackedFiles() {
MutexLock l(&mu_);
return tracked_files_;
}
int64_t SstFileManagerImpl::GetDeleteRateBytesPerSecond() {
return delete_scheduler_.GetRateBytesPerSecond();
}
void SstFileManagerImpl::SetDeleteRateBytesPerSecond(int64_t delete_rate) {
return delete_scheduler_.SetRateBytesPerSecond(delete_rate);
}
double SstFileManagerImpl::GetMaxTrashDBRatio() {
return delete_scheduler_.GetMaxTrashDBRatio();
}
void SstFileManagerImpl::SetMaxTrashDBRatio(double r) {
return delete_scheduler_.SetMaxTrashDBRatio(r);
}
uint64_t SstFileManagerImpl::GetTotalTrashSize() {
return delete_scheduler_.GetTotalTrashSize();
}
void SstFileManagerImpl::ReserveDiskBuffer(uint64_t size,
const std::string& path) {
MutexLock l(&mu_);
reserved_disk_buffer_ += size;
if (path_.empty()) {
path_ = path;
}
}
void SstFileManagerImpl::ClearError() {
while (true) {
MutexLock l(&mu_);
if (error_handler_list_.empty() || closing_) {
return;
}
uint64_t free_space = 0;
Status s = fs_->GetFreeSpace(path_, IOOptions(), &free_space, nullptr);
free_space = max_allowed_space_ > 0
? std::min(max_allowed_space_, free_space)
: free_space;
if (s.ok()) {
// In case of multi-DB instances, some of them may have experienced a
// soft error and some a hard error. In the SstFileManagerImpl, a hard
// error will basically override previously reported soft errors. Once
// we clear the hard error, we don't keep track of previous errors for
// now
if (bg_err_.severity() == Status::Severity::kHardError) {
if (free_space < reserved_disk_buffer_) {
ROCKS_LOG_ERROR(logger_,
"free space [%" PRIu64
" bytes] is less than "
"required disk buffer [%" PRIu64 " bytes]\n",
free_space, reserved_disk_buffer_);
ROCKS_LOG_ERROR(logger_, "Cannot clear hard error\n");
s = Status::NoSpace();
}
} else if (bg_err_.severity() == Status::Severity::kSoftError) {
if (free_space < free_space_trigger_) {
ROCKS_LOG_WARN(logger_,
"free space [%" PRIu64
" bytes] is less than "
"free space for compaction trigger [%" PRIu64
" bytes]\n",
free_space, free_space_trigger_);
ROCKS_LOG_WARN(logger_, "Cannot clear soft error\n");
s = Status::NoSpace();
}
}
}
// Someone could have called CancelErrorRecovery() and the list could have
// become empty, so check again here
if (s.ok()) {
assert(!error_handler_list_.empty());
auto error_handler = error_handler_list_.front();
// Since we will release the mutex, set cur_instance_ to signal to the
// shutdown thread, if it calls // CancelErrorRecovery() the meantime,
// to indicate that this DB instance is busy. The DB instance is
// guaranteed to not be deleted before RecoverFromBGError() returns,
// since the ErrorHandler::recovery_in_prog_ flag would be true
cur_instance_ = error_handler;
mu_.Unlock();
s = error_handler->RecoverFromBGError();
TEST_SYNC_POINT("SstFileManagerImpl::ErrorCleared");
mu_.Lock();
// The DB instance might have been deleted while we were
// waiting for the mutex, so check cur_instance_ to make sure its
// still non-null
if (cur_instance_) {
// Check for error again, since the instance may have recovered but
// immediately got another error. If that's the case, and the new
// error is also a NoSpace() non-fatal error, leave the instance in
// the list
Status err = cur_instance_->GetBGError();
if (s.ok() && err.subcode() == IOStatus::SubCode::kNoSpace &&
err.severity() < Status::Severity::kFatalError) {
s = err;
}
cur_instance_ = nullptr;
}
if (s.ok() || s.IsShutdownInProgress() ||
(!s.ok() && s.severity() >= Status::Severity::kFatalError)) {
// If shutdown is in progress, abandon this handler instance
// and continue with the others
error_handler_list_.pop_front();
}
}
if (!error_handler_list_.empty()) {
// If there are more instances to be recovered, reschedule after 5
// seconds
int64_t wait_until = clock_->NowMicros() + 5000000;
cv_.TimedWait(wait_until);
}
// Check again for error_handler_list_ empty, as a DB instance shutdown
// could have removed it from the queue while we were in timed wait
if (error_handler_list_.empty()) {
ROCKS_LOG_INFO(logger_, "Clearing error\n");
bg_err_ = Status::OK();
return;
}
}
}
void SstFileManagerImpl::StartErrorRecovery(ErrorHandler* handler,
Status bg_error) {
MutexLock l(&mu_);
if (bg_error.severity() == Status::Severity::kSoftError) {
if (bg_err_.ok()) {
// Setting bg_err_ basically means we're in degraded mode
// Assume that all pending compactions will fail similarly. The trigger
// for clearing this condition is set to current compaction reserved
// size, so we stop checking disk space available in
// EnoughRoomForCompaction once this much free space is available
bg_err_ = bg_error;
}
} else if (bg_error.severity() == Status::Severity::kHardError) {
bg_err_ = bg_error;
} else {
assert(false);
}
// If this is the first instance of this error, kick of a thread to poll
// and recover from this condition
if (error_handler_list_.empty()) {
error_handler_list_.push_back(handler);
// Release lock before calling join. Its ok to do so because
// error_handler_list_ is now non-empty, so no other invocation of this
// function will execute this piece of code
mu_.Unlock();
if (bg_thread_) {
bg_thread_->join();
}
// Start a new thread. The previous one would have exited.
bg_thread_.reset(new port::Thread(&SstFileManagerImpl::ClearError, this));
mu_.Lock();
} else {
// Check if this DB instance is already in the list
for (auto iter = error_handler_list_.begin();
iter != error_handler_list_.end(); ++iter) {
if ((*iter) == handler) {
return;
}
}
error_handler_list_.push_back(handler);
}
}
bool SstFileManagerImpl::CancelErrorRecovery(ErrorHandler* handler) {
MutexLock l(&mu_);
if (cur_instance_ == handler) {
// This instance is currently busy attempting to recover
// Nullify it so the recovery thread doesn't attempt to access it again
cur_instance_ = nullptr;
return false;
}
for (auto iter = error_handler_list_.begin();
iter != error_handler_list_.end(); ++iter) {
if ((*iter) == handler) {
error_handler_list_.erase(iter);
return true;
}
}
return false;
}
Status SstFileManagerImpl::ScheduleFileDeletion(
const std::string& file_path, const std::string& path_to_sync,
const bool force_bg) {
TEST_SYNC_POINT_CALLBACK("SstFileManagerImpl::ScheduleFileDeletion",
const_cast<std::string*>(&file_path));
return delete_scheduler_.DeleteFile(file_path, path_to_sync,
force_bg);
}
void SstFileManagerImpl::WaitForEmptyTrash() {
delete_scheduler_.WaitForEmptyTrash();
}
void SstFileManagerImpl::OnAddFileImpl(const std::string& file_path,
uint64_t file_size) {
auto tracked_file = tracked_files_.find(file_path);
if (tracked_file != tracked_files_.end()) {
// File was added before, we will just update the size
total_files_size_ -= tracked_file->second;
total_files_size_ += file_size;
cur_compactions_reserved_size_ -= file_size;
} else {
total_files_size_ += file_size;
}
tracked_files_[file_path] = file_size;
}
void SstFileManagerImpl::OnDeleteFileImpl(const std::string& file_path) {
auto tracked_file = tracked_files_.find(file_path);
if (tracked_file == tracked_files_.end()) {
// File is not tracked
return;
}
total_files_size_ -= tracked_file->second;
tracked_files_.erase(tracked_file);
}
SstFileManager* NewSstFileManager(Env* env, std::shared_ptr<Logger> info_log,
std::string trash_dir,
int64_t rate_bytes_per_sec,
bool delete_existing_trash, Status* status,
double max_trash_db_ratio,
uint64_t bytes_max_delete_chunk) {
const auto& fs = env->GetFileSystem();
return NewSstFileManager(env, fs, info_log, trash_dir, rate_bytes_per_sec,
delete_existing_trash, status, max_trash_db_ratio,
bytes_max_delete_chunk);
}
SstFileManager* NewSstFileManager(Env* env, std::shared_ptr<FileSystem> fs,
std::shared_ptr<Logger> info_log,
const std::string& trash_dir,
int64_t rate_bytes_per_sec,
bool delete_existing_trash, Status* status,
double max_trash_db_ratio,
uint64_t bytes_max_delete_chunk) {
const auto& clock = env->GetSystemClock();
SstFileManagerImpl* res =
new SstFileManagerImpl(clock, fs, info_log, rate_bytes_per_sec,
max_trash_db_ratio, bytes_max_delete_chunk);
// trash_dir is deprecated and not needed anymore, but if user passed it
// we will still remove files in it.
Status s = Status::OK();
if (delete_existing_trash && trash_dir != "") {
std::vector<std::string> files_in_trash;
s = fs->GetChildren(trash_dir, IOOptions(), &files_in_trash, nullptr);
if (s.ok()) {
for (const std::string& trash_file : files_in_trash) {
std::string path_in_trash = trash_dir + "/" + trash_file;
res->OnAddFile(path_in_trash);
Status file_delete =
res->ScheduleFileDeletion(path_in_trash, trash_dir);
if (s.ok() && !file_delete.ok()) {
s = file_delete;
}
}
}
}
if (status) {
*status = s;
} else {
// No one passed us a Status, so they must not care about the error...
s.PermitUncheckedError();
}
return res;
}
#else
SstFileManager* NewSstFileManager(Env* /*env*/,
std::shared_ptr<Logger> /*info_log*/,
std::string /*trash_dir*/,
int64_t /*rate_bytes_per_sec*/,
bool /*delete_existing_trash*/,
Status* status, double /*max_trash_db_ratio*/,
uint64_t /*bytes_max_delete_chunk*/) {
if (status) {
*status =
Status::NotSupported("SstFileManager is not supported in ROCKSDB_LITE");
}
return nullptr;
}
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE