void Rvm::DestroySegment(std::string segname) {
// Search for a segment with the given name
std::unordered_map<std::string, RvmSegment*>::iterator segment = name_to_segment_map_.find(segname);
if (segment == name_to_segment_map_.end()) {
// Create a one-off transaction that indicates the segment was destroyed
trans_t tid = get_next_transaction_id();
// Write to redo log that the segment was destroyed
RedoRecord* record = new RedoRecord(RedoRecord::DESTROY_SEGMENT, segname);
std::list<RedoRecord*> records;
records.push_back(record);
RvmTransaction* rvm_trans = new RvmTransaction(tid, this, records);
CommitTransaction(rvm_trans); // Commit the transaction
std::string segpath = construct_segment_path(segname);
if (file_exists(segpath)) {
// Delete the file if it exists
if (remove(segpath.c_str()) != 0) {
#if DEBUG
std::cerr << "Rvm::DestroySegment(): Error deleting file" << std::endl;
#endif
}
}
} else {
#if DEBUG
std::cout << "Rvm::DestroySegment(): Segment " << segname << " already mapped." << std::endl;
#endif
// Trying to destroy a segment that is currently mapped
return;
}
}
trans_t Rvm::BeginTransaction(int numsegs, void** segbases) {
// Check to see that input segment bases are valid
for (int i = 0; i < numsegs; i++) {
std::unordered_map<void*, RvmSegment*>::iterator iterator = base_to_segment_map_.find(segbases[i]);
// Make sure segment exists
if (iterator != base_to_segment_map_.end()) {
RvmSegment* rvm_segment = iterator->second;
// Check if segment is already owned by another transaction
if (rvm_segment->has_owner()) {
#if DEBUG
std::cerr << "Rvm::BeginTransaction(): Segment " << rvm_segment->get_name() << " being modified by another transaction" << std::endl;
#endif
return (trans_t)-1;
}
} else {
#if DEBUG
std::cerr << "Rvm::BeginTransaction(): Segment " << segbases[i] << " does not exist" << std::endl;
#endif
return (trans_t)-1;
}
}
// Create the transaction
trans_t tid = get_next_transaction_id();
RvmTransaction* rvm_trans = new RvmTransaction(tid, this);
g_trans_map[tid] = rvm_trans;
for (int i = 0; i < numsegs; i++) {
RvmSegment* rvm_segment = base_to_segment_map_[segbases[i]];
rvm_trans->AddSegment(rvm_segment);
}
return tid;
}
void Rvm::TruncateLog() {
std::unordered_map<std::string, std::list<RedoRecord*>> commit_map;
std::list<RedoRecord*> unbacked_records;
for (RvmTransaction* rvm_trans : committed_transactions_) {
// Loop through logs and separate based on which backing file
// the logs apply to
for (RedoRecord* record : rvm_trans->get_redo_records()) {
if (record->get_type() == RedoRecord::RecordType::DESTROY_SEGMENT) {
// If it is a delete record, then clear current list
commit_map[record->get_segment_name()].clear();
} else {
// Regular record, so push back to commit list
commit_map[record->get_segment_name()].push_back(record);
}
}
// Clear the list of redo records
rvm_trans->clear_redo_records();
delete rvm_trans;
}
committed_transactions_.clear();
// Loop through map and commit logs to backing file
for (auto& pair : commit_map) {
if (!pair.second.empty()) {
bool success = ApplyRecordsToBackingFile(pair.first, pair.second);
if (!success) {
// Logs not successfully applied, so save them
for (RedoRecord* record : pair.second) {
unbacked_records.push_back(record);
}
} else {
// Successfully applied records, so delete them
for (RedoRecord* record : pair.second) {
delete record;
}
}
}
}
std::ofstream::openmode flags = std::ofstream::out | std::ofstream::binary | std::ofstream::trunc;
std::ofstream log_file(tmp_log_path_, flags);
if (!unbacked_records.empty()) {
RvmTransaction* rvm_trans = new RvmTransaction(get_next_transaction_id(), this, unbacked_records);
WriteTransactionToLog(log_file, rvm_trans);
log_file.flush();
committed_transactions_.push_back(rvm_trans);
}
// Make the temporary log file as the new log file
std::remove(log_path_.c_str());
std::rename(tmp_log_path_.c_str(), log_path_.c_str());
}
void init_isns_hdr(struct isns_hdr *hdr, int function_id, int replace)
{
hdr->isnsp_version = htons((u16)ISNSP_VERSION);
hdr->function_id = htons((u16)function_id);
hdr->pdu_length = 0;
hdr->flags = 0;
/* always use one PDU for one command we send */
set_bit_first_pdu(hdr->flags);
set_bit_last_pdu(hdr->flags);
set_bit_sender_client(hdr->flags);
if (replace)
set_bit_replace(hdr->flags);
hdr->flags = htons((u16)hdr->flags);
get_next_transaction_id(&hdr->transaction_id);
hdr->transaction_id = htons((u16)hdr->transaction_id);
hdr->sequence_id = 0;
}