Revert "SERVER-31174 Move the sessions collection to config.system.sessions"

This reverts commit ba1704f7cbc0b9a03a181df145f75f433a59b7df.

6 files changed, 65 insertions, 80 deletions

diff --git a/src/mongo/db/namespace_string.cpp b/src/mongo/db/namespace_string.cpp
index 035228b65ad..35fbde965dd 100644
--- a/src/mongo/db/namespace_string.cpp
+++ b/src/mongo/db/namespace_string.cpp
@@ -115,8 +115,7 @@ bool NamespaceString::isLegalClientSystemNS() const {
             return true;
         if (ns() == "admin.system.backup_users")
             return true;
-    } else if (db() == "config") {
-        if (ns() == "config.system.sessions")
+        if (ns() == "admin.system.sessions")
             return true;
     }
     if (ns() == "local.system.replset")
diff --git a/src/mongo/db/ops/insert.cpp b/src/mongo/db/ops/insert.cpp
index de02fda5642..0b422f8882c 100644
--- a/src/mongo/db/ops/insert.cpp
+++ b/src/mongo/db/ops/insert.cpp
@@ -235,6 +235,8 @@ Status userAllowedCreateNS(StringData db, StringData coll) {
         if (db == "admin") {
             if (coll == "system.version")
                 return Status::OK();
+            if (coll == "system.sessions")
+                return Status::OK();
             if (coll == "system.roles")
                 return Status::OK();
             if (coll == "system.new_users")
@@ -244,10 +246,6 @@ Status userAllowedCreateNS(StringData db, StringData coll) {
             if (coll == "system.keys")
                 return Status::OK();
         }
-        if (db == "config") {
-            if (coll == "system.sessions")
-                return Status::OK();
-        }
         if (db == "local") {
             if (coll == "system.replset")
                 return Status::OK();
diff --git a/src/mongo/db/pipeline/document_source_list_sessions.h b/src/mongo/db/pipeline/document_source_list_sessions.h
index 47c08af9d73..38ba2b21b67 100644
--- a/src/mongo/db/pipeline/document_source_list_sessions.h
+++ b/src/mongo/db/pipeline/document_source_list_sessions.h
@@ -37,7 +37,7 @@ namespace mongo {
 
 /**
  * $listSessions: { allUsers: true/false, users: [ {user:"jsmith", db:"test"}, ... ] }
- * Return all sessions in the config.system.sessions collection
+ * Return all sessions in the admin.system.sessions collection
  * or just sessions for the currently logged in user. (Default: false)
  *
  * This is essentially an alias for {$match:{"_id.uid": myid}} or {$match:{}}
diff --git a/src/mongo/db/sessions_collection.h b/src/mongo/db/sessions_collection.h
index 63fd34667cf..9d29924069c 100644
--- a/src/mongo/db/sessions_collection.h
+++ b/src/mongo/db/sessions_collection.h
@@ -49,9 +49,9 @@ class SessionsCollection {
 public:
     virtual ~SessionsCollection();
 
-    static constexpr StringData kSessionsDb = "config"_sd;
+    static constexpr StringData kSessionsDb = "admin"_sd;
     static constexpr StringData kSessionsCollection = "system.sessions"_sd;
-    static constexpr StringData kSessionsFullNS = "config.system.sessions"_sd;
+    static constexpr StringData kSessionsFullNS = "admin.system.sessions"_sd;
 
     static const NamespaceString kSessionsNamespaceString;
 
diff --git a/src/mongo/db/system_index.cpp b/src/mongo/db/system_index.cpp
index be95f1d0758..0c07a4e46ad 100644
--- a/src/mongo/db/system_index.cpp
+++ b/src/mongo/db/system_index.cpp
@@ -67,7 +67,7 @@ IndexSpec v3SystemUsersIndexSpec;
 IndexSpec v3SystemRolesIndexSpec;
 IndexSpec v1SystemSessionsIndexSpec;
 
-const NamespaceString sessionCollectionNamespace("config.system.sessions");
+const NamespaceString sessionCollectionNamespace("admin.system.sessions");
 
 MONGO_INITIALIZER(AuthIndexKeyPatterns)(InitializerContext*) {
     v1SystemUsersKeyPattern = BSON("user" << 1 << "userSource" << 1);
@@ -145,84 +145,72 @@ Status verifySystemIndexes(OperationContext* opCtx) {
     const NamespaceString& systemUsers = AuthorizationManager::usersCollectionNamespace;
     const NamespaceString& systemRoles = AuthorizationManager::rolesCollectionNamespace;
 
-    // Create indexes for collections on the admin db
-    {
-        AutoGetDb autoDb(opCtx, systemUsers.db(), MODE_X);
-        if (!autoDb.getDb()) {
-            return Status::OK();
-        }
-
-        Collection* collection = autoDb.getDb()->getCollection(opCtx, systemUsers);
-        if (collection) {
-            IndexCatalog* indexCatalog = collection->getIndexCatalog();
-            invariant(indexCatalog);
-
-            // Make sure the old unique index from v2.4 on system.users doesn't exist.
-            std::vector<IndexDescriptor*> indexes;
-            indexCatalog->findIndexesByKeyPattern(opCtx, v1SystemUsersKeyPattern, false, &indexes);
-
-            if (!indexes.empty()) {
-                fassert(ErrorCodes::AmbiguousIndexKeyPattern, indexes.size() == 1);
-                return Status(ErrorCodes::AuthSchemaIncompatible,
-                              "Old 2.4 style user index identified. "
-                              "The authentication schema needs to be updated by "
-                              "running authSchemaUpgrade on a 2.6 server.");
-            }
+    AutoGetDb autoDb(opCtx, systemUsers.db(), MODE_X);
+    if (!autoDb.getDb()) {
+        return Status::OK();
+    }
 
-            // Ensure that system indexes exist for the user collection
-            indexCatalog->findIndexesByKeyPattern(opCtx, v3SystemUsersKeyPattern, false, &indexes);
-            if (indexes.empty()) {
-                try {
-                    generateSystemIndexForExistingCollection(
-                        opCtx, collection, systemUsers, v3SystemUsersIndexSpec);
-                } catch (...) {
-                    return exceptionToStatus();
-                }
-            }
+    Collection* collection = autoDb.getDb()->getCollection(opCtx, systemUsers);
+    if (collection) {
+        IndexCatalog* indexCatalog = collection->getIndexCatalog();
+        invariant(indexCatalog);
+
+        // Make sure the old unique index from v2.4 on system.users doesn't exist.
+        std::vector<IndexDescriptor*> indexes;
+        indexCatalog->findIndexesByKeyPattern(opCtx, v1SystemUsersKeyPattern, false, &indexes);
+
+        if (!indexes.empty()) {
+            fassert(ErrorCodes::AmbiguousIndexKeyPattern, indexes.size() == 1);
+            return Status(ErrorCodes::AuthSchemaIncompatible,
+                          "Old 2.4 style user index identified. "
+                          "The authentication schema needs to be updated by "
+                          "running authSchemaUpgrade on a 2.6 server.");
         }
 
-        // Ensure that system indexes exist for the roles collection, if it exists.
-        collection = autoDb.getDb()->getCollection(opCtx, systemRoles);
-        if (collection) {
-            IndexCatalog* indexCatalog = collection->getIndexCatalog();
-            invariant(indexCatalog);
-
-            std::vector<IndexDescriptor*> indexes;
-            indexCatalog->findIndexesByKeyPattern(opCtx, v3SystemRolesKeyPattern, false, &indexes);
-            if (indexes.empty()) {
-                try {
-                    generateSystemIndexForExistingCollection(
-                        opCtx, collection, systemRoles, v3SystemRolesIndexSpec);
-                } catch (...) {
-                    return exceptionToStatus();
-                }
+        // Ensure that system indexes exist for the user collection
+        indexCatalog->findIndexesByKeyPattern(opCtx, v3SystemUsersKeyPattern, false, &indexes);
+        if (indexes.empty()) {
+            try {
+                generateSystemIndexForExistingCollection(
+                    opCtx, collection, systemUsers, v3SystemUsersIndexSpec);
+            } catch (...) {
+                return exceptionToStatus();
             }
         }
     }
 
-    // Create indexes for system collections in the config db.
-    {
-        AutoGetDb autoDb(opCtx, sessionCollectionNamespace.db(), MODE_X);
-        if (!autoDb.getDb()) {
-            return Status::OK();
+    // Ensure that system indexes exist for the roles collection, if it exists.
+    collection = autoDb.getDb()->getCollection(opCtx, systemRoles);
+    if (collection) {
+        IndexCatalog* indexCatalog = collection->getIndexCatalog();
+        invariant(indexCatalog);
+
+        std::vector<IndexDescriptor*> indexes;
+        indexCatalog->findIndexesByKeyPattern(opCtx, v3SystemRolesKeyPattern, false, &indexes);
+        if (indexes.empty()) {
+            try {
+                generateSystemIndexForExistingCollection(
+                    opCtx, collection, systemRoles, v3SystemRolesIndexSpec);
+            } catch (...) {
+                return exceptionToStatus();
+            }
         }
+    }
 
-        // Ensure that system indexes exist for the sessions collection, if it exists.
-        auto collection = autoDb.getDb()->getCollection(opCtx, sessionCollectionNamespace);
-        if (collection) {
-            IndexCatalog* indexCatalog = collection->getIndexCatalog();
-            invariant(indexCatalog);
-
-            std::vector<IndexDescriptor*> indexes;
-            indexCatalog->findIndexesByKeyPattern(
-                opCtx, v1SystemSessionsKeyPattern, false, &indexes);
-            if (indexes.empty()) {
-                try {
-                    generateSystemIndexForExistingCollection(
-                        opCtx, collection, sessionCollectionNamespace, v1SystemSessionsIndexSpec);
-                } catch (...) {
-                    return exceptionToStatus();
-                }
+    // Ensure that system indexes exist for the sessions collection, if it exists.
+    collection = autoDb.getDb()->getCollection(opCtx, sessionCollectionNamespace);
+    if (collection) {
+        IndexCatalog* indexCatalog = collection->getIndexCatalog();
+        invariant(indexCatalog);
+
+        std::vector<IndexDescriptor*> indexes;
+        indexCatalog->findIndexesByKeyPattern(opCtx, v1SystemSessionsKeyPattern, false, &indexes);
+        if (indexes.empty()) {
+            try {
+                generateSystemIndexForExistingCollection(
+                    opCtx, collection, sessionCollectionNamespace, v1SystemSessionsIndexSpec);
+            } catch (...) {
+                return exceptionToStatus();
             }
         }
     }
diff --git a/src/mongo/dbtests/logical_sessions_tests.cpp b/src/mongo/dbtests/logical_sessions_tests.cpp
index 0b1b42df660..13ca0c434c8 100644
--- a/src/mongo/dbtests/logical_sessions_tests.cpp
+++ b/src/mongo/dbtests/logical_sessions_tests.cpp
@@ -45,7 +45,7 @@
 namespace LogicalSessionTests {
 
 namespace {
-constexpr StringData kTestNS = "config.system.sessions"_sd;
+constexpr StringData kTestNS = "admin.system.sessions"_sd;
 
 LogicalSessionRecord makeRecord(Date_t time = Date_t::now()) {
     auto record = makeLogicalSessionRecordForTest();