ClientCursor::~ClientCursor() {
// Cursors must be unpinned and deregistered from their cursor manager before being deleted.
invariant(!_operationUsingCursor);
invariant(_disposed);
cursorStatsOpen.decrement();
if (isNoTimeout()) {
cursorStatsOpenNoTimeout.decrement();
}
}
void CursorCache::removeRef(long long id) {
verify(id);
stdx::lock_guard<stdx::mutex> lk(_mutex);
_refs.erase(id);
_refsNS.erase(id);
cursorStatsSingleTarget.decrement();
}
void ClientCursorPin::deleteUnderlying() {
invariant(_cursor);
invariant(_cursor->_operationUsingCursor);
// Note the following subtleties of this method's implementation:
// - We must unpin the cursor before destruction, since it is an error to delete a pinned
// cursor.
// - In addition, we must deregister the cursor before unpinning, since it is an
// error to unpin a registered cursor without holding the cursor manager lock (note that
// we can't simply unpin with the cursor manager lock here, since we need to guarantee
// exclusive ownership of the cursor when we are deleting it).
// Note it's not safe to dereference _cursor->_cursorManager unless we know we haven't been
// killed. If we're not locked we assume we haven't been killed because we're working with the
// global cursor manager which never kills cursors.
dassert(_opCtx->lockState()->isCollectionLockedForMode(_cursor->_nss.ns(), MODE_IS) ||
_cursor->_cursorManager->isGlobalManager());
if (!_cursor->getExecutor()->isMarkedAsKilled()) {
_cursor->_cursorManager->deregisterCursor(_cursor);
}
// Make sure the cursor is disposed and unpinned before being destroyed.
_cursor->dispose(_opCtx);
_cursor->_operationUsingCursor = nullptr;
delete _cursor;
cursorStatsOpenPinned.decrement();
_cursor = nullptr;
}
void CursorCache::removeRef(long long id) {
verify(id);
scoped_lock lk(_mutex);
_refs.erase(id);
_refsNS.erase(id);
cursorStatsSingleTarget.decrement();
}
void ClientCursorPin::release() {
if (!_cursor)
return;
// Note it's not safe to dereference _cursor->_cursorManager unless we know we haven't been
// killed. If we're not locked we assume we haven't been killed because we're working with the
// global cursor manager which never kills cursors.
dassert(_opCtx->lockState()->isCollectionLockedForMode(_cursor->_nss.ns(), MODE_IS) ||
_cursor->_cursorManager->isGlobalManager());
invariant(_cursor->_operationUsingCursor);
if (_cursor->getExecutor()->isMarkedAsKilled()) {
// The ClientCursor was killed while we had it. Therefore, it is our responsibility to
// call dispose() and delete it.
deleteUnderlying();
} else {
// Unpin the cursor under the collection cursor manager lock.
_cursor->_cursorManager->unpin(_opCtx, _cursor);
cursorStatsOpenPinned.decrement();
}
_cursor = nullptr;
}
void CursorCache::gotKillCursors(Message& m) {
LastError::get(cc()).disable();
DbMessage dbmessage(m);
int n = dbmessage.pullInt();
if (n > 2000) {
(n < 30000 ? warning() : error()) << "receivedKillCursors, n=" << n << endl;
}
uassert(13286, "sent 0 cursors to kill", n >= 1);
uassert(13287, "too many cursors to kill", n < 30000);
massert(18632,
str::stream() << "bad kill cursors size: " << m.dataSize(),
m.dataSize() == 8 + (8 * n));
ConstDataCursor cursors(dbmessage.getArray(n));
ClientBasic* client = ClientBasic::getCurrent();
AuthorizationSession* authSession = AuthorizationSession::get(client);
for (int i = 0; i < n; i++) {
long long id = cursors.readAndAdvance<LittleEndian<int64_t>>();
LOG(_myLogLevel) << "CursorCache::gotKillCursors id: " << id << endl;
if (!id) {
warning() << " got cursor id of 0 to kill" << endl;
continue;
}
string server;
{
stdx::lock_guard<stdx::mutex> lk(_mutex);
MapSharded::iterator i = _cursors.find(id);
if (i != _cursors.end()) {
Status authorizationStatus =
authSession->checkAuthForKillCursors(NamespaceString(i->second->getNS()), id);
audit::logKillCursorsAuthzCheck(
client,
NamespaceString(i->second->getNS()),
id,
authorizationStatus.isOK() ? ErrorCodes::OK : ErrorCodes::Unauthorized);
if (authorizationStatus.isOK()) {
_cursorsMaxTimeMS.erase(i->second->getId());
_cursors.erase(i);
}
continue;
}
MapNormal::iterator refsIt = _refs.find(id);
MapNormal::iterator refsNSIt = _refsNS.find(id);
if (refsIt == _refs.end()) {
warning() << "can't find cursor: " << id << endl;
continue;
}
verify(refsNSIt != _refsNS.end());
Status authorizationStatus =
authSession->checkAuthForKillCursors(NamespaceString(refsNSIt->second), id);
audit::logKillCursorsAuthzCheck(client,
NamespaceString(refsNSIt->second),
id,
authorizationStatus.isOK() ? ErrorCodes::OK
: ErrorCodes::Unauthorized);
if (!authorizationStatus.isOK()) {
continue;
}
server = refsIt->second;
_refs.erase(refsIt);
_refsNS.erase(refsNSIt);
cursorStatsSingleTarget.decrement();
}
LOG(_myLogLevel) << "CursorCache::found gotKillCursors id: " << id << " server: " << server
<< endl;
verify(server.size());
ScopedDbConnection conn(server);
conn->killCursor(id);
conn.done();
}
}
ShardedClientCursor::~ShardedClientCursor() {
verify(_cursor);
delete _cursor;
_cursor = 0;
cursorStatsMultiTarget.decrement();
}