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Fix transaction abort object deletion in storage v2

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Reviewers: mtomic, teon.banek

Reviewed By: mtomic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2198
This commit is contained in:
Matej Ferencevic 2019-07-11 15:10:14 +02:00
parent d9a6775656
commit 15c959dfb5
1 changed files with 13 additions and 14 deletions
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27
src/storage/v2/storage.cpp
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@ -321,12 +321,20 @@ void Storage::Accessor::Commit() {
void Storage::Accessor::Abort() {
CHECK(is_transaction_active_) << "The transaction is already terminated!";
// We acquire accessors to the storage `SkipList`s so that we can safely
// delete objects in the lists. While the accessor is alive, all objects (even
// deleted ones) are guaranteed to still exist and pointers to them are still
// valid.
auto vertex_acc = storage_->vertices_.access();
auto edge_acc = storage_->edges_.access();
for (const auto &delta : transaction_.deltas) {
auto prev = delta.prev.Get();
switch (prev.type) {
case PreviousPtr::Type::VERTEX: {
auto vertex = prev.vertex;
std::unique_lock<utils::SpinLock> guard(vertex->lock);
std::lock_guard<utils::SpinLock> guard(vertex->lock);
Delta *current = vertex->delta;
while (current != nullptr &&
current->timestamp->load(std::memory_order_acquire) ==
@ -406,12 +414,8 @@ void Storage::Accessor::Abort() {
break;
}
case Delta::Action::DELETE_OBJECT: {
auto acc = storage_->vertices_.access();
// We must unlock the guard here. Otherwise it might try to access
// freed memory in its destructor because the vertex is deleted
// along with its lock.
guard.unlock();
CHECK(acc.remove(vertex->gid)) << "Invalid database state!";
CHECK(vertex_acc.remove(vertex->gid))
<< "Invalid database state!";
break;
}
case Delta::Action::RECREATE_OBJECT: {
@ -430,7 +434,7 @@ void Storage::Accessor::Abort() {
}
case PreviousPtr::Type::EDGE: {
auto edge = prev.edge;
std::unique_lock<utils::SpinLock> guard(edge->lock);
std::lock_guard<utils::SpinLock> guard(edge->lock);
Delta *current = edge->delta;
while (current != nullptr &&
current->timestamp->load(std::memory_order_acquire) ==
@ -453,12 +457,7 @@ void Storage::Accessor::Abort() {
break;
}
case Delta::Action::DELETE_OBJECT: {
auto acc = storage_->edges_.access();
// We must unlock the guard here. Otherwise it might try to access
// freed memory in its destructor because the edge is deleted
// along with its lock.
guard.unlock();
CHECK(acc.remove(edge->gid)) << "Invalid database state!";
CHECK(edge_acc.remove(edge->gid)) << "Invalid database state!";
break;
}
case Delta::Action::RECREATE_OBJECT: {