Merge pull request #657

1995923 BlockchainLMDB: Deal with DB exceptions at block level with particularity (warptangent)
c16cc20 BlockchainLMDB: Add sanity check for inconsistent state (warptangent)
9118d0a BlockchainLMDB: Call destructor on allocated txn if setup fails (warptangent)
f5581c3 BlockchainLMDB: Replace remaining txn pointer NULLs with nullptr (warptangent)
This commit is contained in:
Riccardo Spagni 2016-02-13 19:54:47 +02:00
commit 63e2d4195b
No known key found for this signature in database
GPG Key ID: 55432DF31CCD4FCD
2 changed files with 50 additions and 12 deletions

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@ -175,6 +175,14 @@ class DB_ERROR : public DB_EXCEPTION
DB_ERROR(const char* s) : DB_EXCEPTION(s) { } DB_ERROR(const char* s) : DB_EXCEPTION(s) { }
}; };
// For distinguishing errors trying to set up a DB txn from other errors
class DB_ERROR_TXN_START : public DB_EXCEPTION
{
public:
DB_ERROR_TXN_START() : DB_EXCEPTION("DB Error in starting txn") { }
DB_ERROR_TXN_START(const char* s) : DB_EXCEPTION(s) { }
};
class DB_OPEN_FAILURE : public DB_EXCEPTION class DB_OPEN_FAILURE : public DB_EXCEPTION
{ {
public: public:

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@ -235,7 +235,7 @@ mdb_txn_safe::mdb_txn_safe() : m_txn(NULL)
mdb_txn_safe::~mdb_txn_safe() mdb_txn_safe::~mdb_txn_safe()
{ {
LOG_PRINT_L3("mdb_txn_safe: destructor"); LOG_PRINT_L3("mdb_txn_safe: destructor");
if (m_txn != NULL) if (m_txn != nullptr)
{ {
if (m_batch_txn) // this is a batch txn and should have been handled before this point for safety if (m_batch_txn) // this is a batch txn and should have been handled before this point for safety
{ {
@ -265,19 +265,19 @@ void mdb_txn_safe::commit(std::string message)
if (auto result = mdb_txn_commit(m_txn)) if (auto result = mdb_txn_commit(m_txn))
{ {
m_txn = NULL; m_txn = nullptr;
throw0(DB_ERROR((message + ": ").append(mdb_strerror(result)).c_str())); throw0(DB_ERROR((message + ": ").append(mdb_strerror(result)).c_str()));
} }
m_txn = NULL; m_txn = nullptr;
} }
void mdb_txn_safe::abort() void mdb_txn_safe::abort()
{ {
LOG_PRINT_L3("mdb_txn_safe: abort()"); LOG_PRINT_L3("mdb_txn_safe: abort()");
if(m_txn != NULL) if(m_txn != nullptr)
{ {
mdb_txn_abort(m_txn); mdb_txn_abort(m_txn);
m_txn = NULL; m_txn = nullptr;
} }
else else
{ {
@ -2114,7 +2114,11 @@ void BlockchainLMDB::batch_start(uint64_t batch_num_blocks)
// NOTE: need to make sure it's destroyed properly when done // NOTE: need to make sure it's destroyed properly when done
if (auto mdb_res = mdb_txn_begin(m_env, NULL, 0, *m_write_batch_txn)) if (auto mdb_res = mdb_txn_begin(m_env, NULL, 0, *m_write_batch_txn))
{
delete m_write_batch_txn;
m_write_batch_txn = nullptr;
throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str())); throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str()));
}
// indicates this transaction is for batch transactions, but not whether it's // indicates this transaction is for batch transactions, but not whether it's
// active // active
m_write_batch_txn->m_batch_txn = true; m_write_batch_txn->m_batch_txn = true;
@ -2195,13 +2199,24 @@ void BlockchainLMDB::set_batch_transactions(bool batch_transactions)
void BlockchainLMDB::block_txn_start() void BlockchainLMDB::block_txn_start()
{ {
LOG_PRINT_L3("BlockchainLMDB::" << __func__); LOG_PRINT_L3("BlockchainLMDB::" << __func__);
// Distinguish the exceptions here from exceptions that would be thrown while
// using the txn and committing it.
//
// If an exception is thrown in this setup, we don't want the caller to catch
// it and proceed as if there were an existing write txn, such as trying to
// call block_txn_abort(). It also indicates a serious issue which will
// probably be thrown up another layer.
if (! m_batch_active && m_write_txn) if (! m_batch_active && m_write_txn)
throw0(DB_ERROR((std::string("Attempted to start new write txn when write txn already exists in ")+__FUNCTION__).c_str())); throw0(DB_ERROR_TXN_START((std::string("Attempted to start new write txn when write txn already exists in ")+__FUNCTION__).c_str()));
if (! m_batch_active) if (! m_batch_active)
{ {
m_write_txn = new mdb_txn_safe(); m_write_txn = new mdb_txn_safe();
if (auto mdb_res = mdb_txn_begin(m_env, NULL, 0, *m_write_txn)) if (auto mdb_res = mdb_txn_begin(m_env, NULL, 0, *m_write_txn))
throw0(DB_ERROR(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str())); {
delete m_write_txn;
m_write_txn = nullptr;
throw0(DB_ERROR_TXN_START(lmdb_error("Failed to create a transaction for the db: ", mdb_res).c_str()));
}
} }
} }
@ -2216,7 +2231,7 @@ void BlockchainLMDB::block_txn_stop()
time_commit1 += time1; time_commit1 += time1;
delete m_write_txn; delete m_write_txn;
m_write_txn = NULL; m_write_txn = nullptr;
} }
} }
@ -2224,9 +2239,20 @@ void BlockchainLMDB::block_txn_abort()
{ {
LOG_PRINT_L3("BlockchainLMDB::" << __func__); LOG_PRINT_L3("BlockchainLMDB::" << __func__);
if (! m_batch_active) if (! m_batch_active)
{
if (m_write_txn != nullptr)
{ {
delete m_write_txn; delete m_write_txn;
m_write_txn = NULL; m_write_txn = nullptr;
}
else
{
// This would probably mean an earlier exception was caught, but then we
// proceeded further than we should have.
throw0(DB_ERROR((std::string("BlockchainLMDB::") + __func__ +
std::string(": block-level DB transaction abort called when write txn doesn't exist")
).c_str()));
}
} }
} }
@ -2251,6 +2277,10 @@ uint64_t BlockchainLMDB::add_block(const block& blk, const size_t& block_size, c
{ {
BlockchainDB::add_block(blk, block_size, cumulative_difficulty, coins_generated, txs); BlockchainDB::add_block(blk, block_size, cumulative_difficulty, coins_generated, txs);
} }
catch (DB_ERROR_TXN_START& e)
{
throw;
}
catch (...) catch (...)
{ {
m_num_outputs = num_outputs; m_num_outputs = num_outputs;
@ -2280,7 +2310,7 @@ void BlockchainLMDB::pop_block(block& blk, std::vector<transaction>& txs)
BlockchainDB::pop_block(blk, txs); BlockchainDB::pop_block(blk, txs);
if (! m_batch_active) if (! m_batch_active)
{ {
m_write_txn = NULL; m_write_txn = nullptr;
txn.commit(); txn.commit();
} }
@ -2288,7 +2318,7 @@ void BlockchainLMDB::pop_block(block& blk, std::vector<transaction>& txs)
catch (...) catch (...)
{ {
m_num_outputs = num_outputs; m_num_outputs = num_outputs;
m_write_txn = NULL; m_write_txn = nullptr;
throw; throw;
} }