SERVER-37354 Make _shardsvrShardCollection re-entrant

1 files changed, 179 insertions, 0 deletions

diff --git a/src/mongo/db/s/active_shard_collection_registry.cpp b/src/mongo/db/s/active_shard_collection_registry.cpp
new file mode 100644
index 00000000000..9a168491262
--- /dev/null
+++ b/src/mongo/db/s/active_shard_collection_registry.cpp
@@ -0,0 +1,179 @@
+
+/**
+ *    Copyright (C) 2018-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/s/active_shard_collection_registry.h"
+
+#include "mongo/db/catalog_raii.h"
+#include "mongo/db/s/collection_sharding_runtime.h"
+#include "mongo/db/service_context.h"
+
+namespace mongo {
+namespace {
+
+const auto getRegistry = ServiceContext::declareDecoration<ActiveShardCollectionRegistry>();
+
+bool ActiveShardsvrShardCollectionEqualsNewRequest(const ShardsvrShardCollection& activeRequest,
+                                                   const ShardsvrShardCollection& newRequest) {
+    if (activeRequest.get_shardsvrShardCollection().get() !=
+        newRequest.get_shardsvrShardCollection().get())
+        return false;
+    if (activeRequest.getKey().woCompare(newRequest.getKey()) != 0)
+        return false;
+    if (activeRequest.getUnique() != newRequest.getUnique())
+        return false;
+    if (activeRequest.getNumInitialChunks() != newRequest.getNumInitialChunks())
+        return false;
+    if ((activeRequest.getCollation() && newRequest.getCollation()) &&
+        (activeRequest.getCollation().get().woCompare(newRequest.getCollation().get()) != 0))
+        return false;
+    if (activeRequest.getGetUUIDfromPrimaryShard() != newRequest.getGetUUIDfromPrimaryShard())
+        return false;
+
+    if (activeRequest.getInitialSplitPoints() && newRequest.getInitialSplitPoints()) {
+        if (activeRequest.getInitialSplitPoints().get().size() !=
+            newRequest.getInitialSplitPoints().get().size()) {
+            return false;
+        } else {
+            for (std::size_t i = 0; i < activeRequest.getInitialSplitPoints().get().size(); i++) {
+                if (activeRequest.getInitialSplitPoints().get()[i].woCompare(
+                        newRequest.getInitialSplitPoints().get()[i]) != 0)
+                    return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+}  // namespace
+
+ActiveShardCollectionRegistry::ActiveShardCollectionRegistry() = default;
+
+ActiveShardCollectionRegistry::~ActiveShardCollectionRegistry() {
+    invariant(_activeShardCollectionMap.empty());
+}
+
+ActiveShardCollectionRegistry& ActiveShardCollectionRegistry::get(ServiceContext* service) {
+    return getRegistry(service);
+}
+
+ActiveShardCollectionRegistry& ActiveShardCollectionRegistry::get(OperationContext* opCtx) {
+    return get(opCtx->getServiceContext());
+}
+
+StatusWith<ScopedShardCollection> ActiveShardCollectionRegistry::registerShardCollection(
+    const ShardsvrShardCollection& request) {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    std::string nss = request.get_shardsvrShardCollection().get().ns();
+
+    auto iter = _activeShardCollectionMap.find(nss);
+    if (iter == _activeShardCollectionMap.end()) {
+        auto activeShardCollectionState = ActiveShardCollectionState(request);
+        _activeShardCollectionMap.try_emplace(nss, activeShardCollectionState);
+
+        return {ScopedShardCollection(nss, this, true, activeShardCollectionState.notification)};
+    } else {
+        auto activeShardCollectionState = iter->second;
+
+        if (ActiveShardsvrShardCollectionEqualsNewRequest(activeShardCollectionState.activeRequest,
+                                                          request)) {
+            return {ScopedShardCollection(
+                nss, nullptr, false, activeShardCollectionState.notification)};
+        }
+        return activeShardCollectionState.constructErrorStatus(request);
+    }
+}
+
+void ActiveShardCollectionRegistry::_clearShardCollection(std::string nss) {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    auto iter = _activeShardCollectionMap.find(nss);
+    invariant(iter != _activeShardCollectionMap.end());
+    _activeShardCollectionMap.erase(nss);
+}
+
+Status ActiveShardCollectionRegistry::ActiveShardCollectionState::constructErrorStatus(
+    const ShardsvrShardCollection& request) const {
+    return {ErrorCodes::ConflictingOperationInProgress,
+            str::stream() << "Unable to shard collection "
+                          << request.get_shardsvrShardCollection().get().ns()
+                          << " with arguments:  "
+                          << request.toBSON()
+                          << " because this shard is currently running shard collection on this "
+                          << "collection with arguments: "
+                          << activeRequest.toBSON()};
+}
+
+ScopedShardCollection::ScopedShardCollection(
+    std::string nss,
+    ActiveShardCollectionRegistry* registry,
+    bool shouldExecute,
+    std::shared_ptr<Notification<Status>> completionNotification)
+    : _nss(nss),
+      _registry(registry),
+      _shouldExecute(shouldExecute),
+      _completionNotification(std::move(completionNotification)) {}
+
+ScopedShardCollection::~ScopedShardCollection() {
+    if (_registry && _shouldExecute) {
+        // If this is a newly started shard collection the caller must always signal on completion
+        invariant(*_completionNotification);
+        _registry->_clearShardCollection(_nss);
+    }
+}
+
+ScopedShardCollection::ScopedShardCollection(ScopedShardCollection&& other) {
+    *this = std::move(other);
+}
+
+ScopedShardCollection& ScopedShardCollection::operator=(ScopedShardCollection&& other) {
+    if (&other != this) {
+        _registry = other._registry;
+        other._registry = nullptr;
+        _shouldExecute = other._shouldExecute;
+        _completionNotification = std::move(other._completionNotification);
+        _nss = std::move(other._nss);
+    }
+
+    return *this;
+}
+
+void ScopedShardCollection::signalComplete(Status status) {
+    invariant(_shouldExecute);
+    _completionNotification->set(status);
+}
+
+Status ScopedShardCollection::waitForCompletion(OperationContext* opCtx) {
+    invariant(!_shouldExecute);
+    return _completionNotification->get(opCtx);
+}
+
+}  // namespace mongo