Revert "SERVER-27419 Move cluster 'drop' command to a separate file"

This reverts commit 20bc3f49fafb2c8a8d9e8224e8723cd767549d2c.

8 files changed, 106 insertions, 183 deletions

diff --git a/src/mongo/s/commands/SConscript b/src/mongo/s/commands/SConscript
index 123481cf2a6..2d8b0f7bf34 100644
--- a/src/mongo/s/commands/SConscript
+++ b/src/mongo/s/commands/SConscript
@@ -27,7 +27,6 @@ env.Library(
         'cluster_count_cmd.cpp',
         'cluster_current_op.cpp',
         'cluster_db_stats_cmd.cpp',
-        'cluster_drop_cmd.cpp',
         'cluster_drop_database_cmd.cpp',
         'cluster_enable_sharding_cmd.cpp',
         'cluster_explain.cpp',
diff --git a/src/mongo/s/commands/cluster_commands_common.cpp b/src/mongo/s/commands/cluster_commands_common.cpp
index 65ed5c6882c..529b39be403 100644
--- a/src/mongo/s/commands/cluster_commands_common.cpp
+++ b/src/mongo/s/commands/cluster_commands_common.cpp
@@ -37,6 +37,8 @@
 #include "mongo/db/query/cursor_response.h"
 #include "mongo/s/client/shard_connection.h"
 #include "mongo/s/client/version_manager.h"
+#include "mongo/s/query/cluster_client_cursor_impl.h"
+#include "mongo/s/query/cluster_cursor_manager.h"
 #include "mongo/s/stale_exception.h"
 #include "mongo/util/log.h"
 
diff --git a/src/mongo/s/commands/cluster_commands_common.h b/src/mongo/s/commands/cluster_commands_common.h
index c45e39b1196..b759c14c45e 100644
--- a/src/mongo/s/commands/cluster_commands_common.h
+++ b/src/mongo/s/commands/cluster_commands_common.h
@@ -38,10 +38,17 @@
 
 namespace mongo {
 
+class BSONObj;
+
 class AScopedConnection;
+class ClusterCursorManager;
 class DBClientBase;
 class DBClientCursor;
 
+namespace executor {
+class TaskExecutor;
+}  // namespace executor
+
 /**
  * DEPRECATED - do not use in any new code. All new code must use the TaskExecutor interface
  * instead.
diff --git a/src/mongo/s/commands/cluster_drop_cmd.cpp b/src/mongo/s/commands/cluster_drop_cmd.cpp
deleted file mode 100644
index 86d1118a856..00000000000
--- a/src/mongo/s/commands/cluster_drop_cmd.cpp
+++ /dev/null
@@ -1,152 +0,0 @@
-/**
- *    Copyright (C) 2016 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    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
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    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 GNU Affero General 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.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/base/status.h"
-#include "mongo/db/commands.h"
-#include "mongo/db/operation_context.h"
-#include "mongo/s/catalog/catalog_cache.h"
-#include "mongo/s/catalog/dist_lock_manager.h"
-#include "mongo/s/catalog/sharding_catalog_client.h"
-#include "mongo/s/catalog/type_database.h"
-#include "mongo/s/client/shard_registry.h"
-#include "mongo/s/commands/cluster_commands_common.h"
-#include "mongo/s/config.h"
-#include "mongo/s/grid.h"
-#include "mongo/s/sharding_raii.h"
-#include "mongo/s/stale_exception.h"
-#include "mongo/util/log.h"
-
-namespace mongo {
-namespace {
-
-class DropCmd : public Command {
-public:
-    DropCmd() : Command("drop") {}
-
-    bool slaveOk() const override {
-        return true;
-    }
-
-    bool adminOnly() const override {
-        return false;
-    }
-
-    bool supportsWriteConcern(const BSONObj& cmd) const override {
-        return true;
-    }
-
-    void addRequiredPrivileges(const std::string& dbname,
-                               const BSONObj& cmdObj,
-                               std::vector<Privilege>* out) override {
-        ActionSet actions;
-        actions.addAction(ActionType::dropCollection);
-        out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
-    }
-
-    bool run(OperationContext* txn,
-             const std::string& dbname,
-             BSONObj& cmdObj,
-             int options,
-             std::string& errmsg,
-             BSONObjBuilder& result) override {
-        const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
-
-        auto scopedDbStatus = ScopedShardDatabase::getExisting(txn, dbname);
-        if (scopedDbStatus == ErrorCodes::NamespaceNotFound) {
-            return true;
-        }
-
-        uassertStatusOK(scopedDbStatus.getStatus());
-
-        auto const db = scopedDbStatus.getValue().db();
-
-        if (!db->isShardingEnabled() || !db->isSharded(nss.ns())) {
-            _dropUnshardedCollectionFromShard(txn, db->getPrimaryId(), nss);
-        } else {
-            uassertStatusOK(Grid::get(txn)->catalogClient(txn)->dropCollection(txn, nss));
-            db->markNSNotSharded(nss.ns());
-        }
-
-        return true;
-    }
-
-private:
-    /**
-     * Sends the 'drop' command for the specified collection to the specified shard. Throws
-     * DBException on failure.
-     */
-    static void _dropUnshardedCollectionFromShard(OperationContext* txn,
-                                                  const ShardId& shardId,
-                                                  const NamespaceString& nss) {
-        const auto shardRegistry = Grid::get(txn)->shardRegistry();
-
-        const auto dropCommandBSON = [shardRegistry, txn, &shardId, &nss] {
-            BSONObjBuilder builder;
-            builder.append("drop", nss.coll());
-
-            // Append the chunk version for the specified namespace indicating that we believe it is
-            // not sharded. Collections residing on the config server are never sharded so do not
-            // send the shard version.
-            if (shardId != shardRegistry->getConfigShard()->getId()) {
-                ChunkVersion::UNSHARDED().appendForCommands(&builder);
-            }
-
-            if (!txn->getWriteConcern().usedDefault) {
-                builder.append(WriteConcernOptions::kWriteConcernField,
-                               txn->getWriteConcern().toBSON());
-            }
-
-            return builder.obj();
-        }();
-
-        const auto shard = uassertStatusOK(Grid::get(txn)->shardRegistry()->getShard(txn, shardId));
-        auto cmdDropResult = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
-            txn,
-            ReadPreferenceSetting{ReadPreference::PrimaryOnly},
-            nss.db().toString(),
-            dropCommandBSON,
-            Shard::RetryPolicy::kIdempotent));
-
-        // Special-case SendStaleVersion errors
-        if (cmdDropResult.commandStatus == ErrorCodes::SendStaleConfig) {
-            throw RecvStaleConfigException(
-                str::stream() << "Stale config while dropping collection", cmdDropResult.response);
-        }
-
-        uassertStatusOK(cmdDropResult.commandStatus);
-        uassertStatusOK(cmdDropResult.writeConcernStatus);
-    }
-
-} clusterDropCmd;
-
-}  // namespace
-}  // namespace mongo
diff --git a/src/mongo/s/commands/cluster_drop_database_cmd.cpp b/src/mongo/s/commands/cluster_drop_database_cmd.cpp
index 7dcf02e2213..05ac92c22ed 100644
--- a/src/mongo/s/commands/cluster_drop_database_cmd.cpp
+++ b/src/mongo/s/commands/cluster_drop_database_cmd.cpp
@@ -38,7 +38,6 @@
 #include "mongo/s/catalog/sharding_catalog_client.h"
 #include "mongo/s/catalog/type_database.h"
 #include "mongo/s/client/shard_registry.h"
-#include "mongo/s/commands/cluster_commands_common.h"
 #include "mongo/s/config.h"
 #include "mongo/s/grid.h"
 #include "mongo/s/sharding_raii.h"
@@ -115,23 +114,22 @@ public:
         std::set<std::string> namespaces;
         db->getAllShardedCollections(namespaces);
 
+        std::set<ShardId> allShardIds;
+
         // Drop the database's collections from metadata
         for (const auto& ns : namespaces) {
-            uassertStatusOK(catalogClient->dropCollection(txn, NamespaceString(ns)));
-            db->markNSNotSharded(ns);
+            const auto collectionShards =
+                _dropShardedCollectionFromConfig(txn, NamespaceString(ns));
+            allShardIds.insert(collectionShards.begin(), collectionShards.end());
         }
 
+
         // Drop the database from the primary shard first
         _dropDatabaseFromShard(txn, db->getPrimaryId(), dbname);
 
         // Drop the database from each of the remaining shards
-        {
-            std::vector<ShardId> allShardIds;
-            Grid::get(txn)->shardRegistry()->getAllShardIds(&allShardIds);
-
-            for (const ShardId& shardId : allShardIds) {
-                _dropDatabaseFromShard(txn, shardId, dbname);
-            }
+        for (const ShardId& shardId : allShardIds) {
+            _dropDatabaseFromShard(txn, shardId, dbname);
         }
 
         // Remove the database entry from the metadata
@@ -159,29 +157,52 @@ public:
 
 private:
     /**
-     * Sends the 'dropDatabase' command for the specified database to the specified shard. Throws
+     * Drops the specified sharded collection from the config server metadata only and returns the
+     * set of shards on which it was located when it was being dropped.
+     *
+     * Throws DBException on failure.
+     */
+    static std::set<ShardId> _dropShardedCollectionFromConfig(OperationContext* txn,
+                                                              NamespaceString nss) {
+        auto scopedCMStatus = ScopedChunkManager::refreshAndGet(txn, nss);
+
+        if (scopedCMStatus == ErrorCodes::NamespaceNotFound ||
+            scopedCMStatus == ErrorCodes::NamespaceNotSharded) {
+            // Skip collection if we cannot find it
+            return std::set<ShardId>{};
+        } else if (!scopedCMStatus.isOK()) {
+            uassertStatusOK({scopedCMStatus.getStatus().code(),
+                             str::stream() << "Failed to drop collection " << nss.ns() << " due to "
+                                           << scopedCMStatus.getStatus().reason()});
+        }
+
+        auto const db = scopedCMStatus.getValue().db();
+        auto const cm = scopedCMStatus.getValue().cm();
+
+        std::set<ShardId> shardIds;
+        cm->getAllShardIds(&shardIds);
+
+        uassertStatusOK(Grid::get(txn)->catalogClient(txn)->dropCollection(txn, nss));
+
+        db->invalidateNs(nss.ns());
+
+        return shardIds;
+    }
+
+    /**
+     * Sends the 'drop' command for the specified database to the specified shard. Throws
      * DBException on failure.
      */
     static void _dropDatabaseFromShard(OperationContext* txn,
                                        const ShardId& shardId,
                                        const std::string& dbName) {
-        const auto dropDatabaseCommandBSON = [txn, &dbName] {
-            BSONObjBuilder builder;
-            builder.append("dropDatabase", 1);
-            if (!txn->getWriteConcern().usedDefault) {
-                builder.append(WriteConcernOptions::kWriteConcernField,
-                               txn->getWriteConcern().toBSON());
-            }
-
-            return builder.obj();
-        }();
-
         const auto shard = uassertStatusOK(Grid::get(txn)->shardRegistry()->getShard(txn, shardId));
         auto cmdDropDatabaseResult = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
             txn,
             ReadPreferenceSetting{ReadPreference::PrimaryOnly},
             dbName,
-            dropDatabaseCommandBSON,
+            BSON("dropDatabase" << 1 << WriteConcernOptions::kWriteConcernField
+                                << txn->getWriteConcern().toBSON()),
             Shard::RetryPolicy::kIdempotent));
 
         uassertStatusOK(cmdDropDatabaseResult.commandStatus);
diff --git a/src/mongo/s/commands/commands_public.cpp b/src/mongo/s/commands/commands_public.cpp
index fe17c4650e1..74e94ffc96e 100644
--- a/src/mongo/s/commands/commands_public.cpp
+++ b/src/mongo/s/commands/commands_public.cpp
@@ -537,6 +537,55 @@ public:
 
 } createCmd;
 
+class DropCmd : public PublicGridCommand {
+public:
+    DropCmd() : PublicGridCommand("drop") {}
+    virtual void addRequiredPrivileges(const std::string& dbname,
+                                       const BSONObj& cmdObj,
+                                       std::vector<Privilege>* out) {
+        ActionSet actions;
+        actions.addAction(ActionType::dropCollection);
+        out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
+    }
+
+    virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
+        return true;
+    }
+
+    bool run(OperationContext* txn,
+             const string& dbName,
+             BSONObj& cmdObj,
+             int options,
+             string& errmsg,
+             BSONObjBuilder& result) {
+        auto status = Grid::get(txn)->catalogCache()->getDatabase(txn, dbName);
+        if (!status.isOK()) {
+            if (status == ErrorCodes::NamespaceNotFound) {
+                return true;
+            }
+
+            return appendCommandStatus(result, status.getStatus());
+        }
+
+        const NamespaceString nss(parseNsCollectionRequired(dbName, cmdObj));
+
+        log() << "DROP: " << nss.ns();
+
+        const auto& db = status.getValue();
+        if (!db->isShardingEnabled() || !db->isSharded(nss.ns())) {
+            log() << "\tdrop going to do passthrough";
+            return passthrough(txn, db.get(), cmdObj, result);
+        }
+
+        uassertStatusOK(Grid::get(txn)->catalogClient(txn)->dropCollection(txn, nss));
+
+        // Force a full reload next time the just dropped namespace is accessed
+        db->invalidateNs(nss.ns());
+
+        return true;
+    }
+} dropCmd;
+
 class RenameCollectionCmd : public PublicGridCommand {
 public:
     RenameCollectionCmd() : PublicGridCommand("renameCollection") {}
diff --git a/src/mongo/s/config.cpp b/src/mongo/s/config.cpp
index a9edfdaf99b..9a0194d8139 100644
--- a/src/mongo/s/config.cpp
+++ b/src/mongo/s/config.cpp
@@ -152,7 +152,7 @@ bool DBConfig::isSharded(const string& ns) {
     return i->second.isSharded();
 }
 
-void DBConfig::markNSNotSharded(const std::string& ns) {
+void DBConfig::invalidateNs(const std::string& ns) {
     stdx::lock_guard<stdx::mutex> lk(_lock);
 
     CollectionInfoMap::iterator it = _collections.find(ns);
diff --git a/src/mongo/s/config.h b/src/mongo/s/config.h
index 79893ddb2b2..0cba78036f9 100644
--- a/src/mongo/s/config.h
+++ b/src/mongo/s/config.h
@@ -120,13 +120,10 @@ public:
     ShardId getPrimaryId();
 
     /**
-     * Removes the specified namespace from the set of collections under this database entry so that
-     * from then onwards it will be treated as unsharded.
-     *
-     * Note that this method doesn't do any writes to the config metadata, but simply drops the
-     * specified namespace from the cache.
+     * Removes all cached metadata for the specified namespace so that subsequent attempts to
+     * retrieve it will cause a full reload.
      */
-    void markNSNotSharded(const std::string& ns);
+    void invalidateNs(const std::string& ns);
 
     void enableSharding(OperationContext* txn);