SERVER-40436 Ensure that the 'collMod' command takes a database MODE_X lock during a no-op

1 files changed, 33 insertions, 0 deletions

diff --git a/jstests/noPassthroughWithMongod/coll_mod_takes_database_x_lock.js b/jstests/noPassthroughWithMongod/coll_mod_takes_database_x_lock.js
new file mode 100644
index 00000000000..bf78d13f887
--- /dev/null
+++ b/jstests/noPassthroughWithMongod/coll_mod_takes_database_x_lock.js
@@ -0,0 +1,33 @@
+/**
+ * Ensures that the 'collMod' command takes a database MODE_X lock during a no-op.
+ */
+(function() {
+    'use strict';
+
+    const failpoint = 'hangAfterDatabaseLock';
+    assert.commandWorked(db.adminCommand({configureFailPoint: failpoint, mode: "alwaysOn"}));
+
+    const conn = db.getMongo();
+    db.createCollection('foo');
+
+    // Run a no-op collMod command.
+    const awaitParallelShell = startParallelShell(() => {
+        assert.commandWorked(db.runCommand({collMod: 'foo'}));
+    }, conn.port);
+
+    // Check that the database MODE_X lock is being held by checking in lockInfo.
+    assert.soon(() => {
+        let lockInfo = assert.commandWorked(db.adminCommand({lockInfo: 1})).lockInfo;
+        for (let i = 0; i < lockInfo.length; i++) {
+            let resourceId = lockInfo[i].resourceId;
+            if (resourceId.includes("Database") && resourceId.includes("test")) {
+                return true;
+            }
+        }
+
+        return false;
+    });
+
+    assert.commandWorked(db.adminCommand({configureFailPoint: failpoint, mode: "off"}));
+    awaitParallelShell();
+})();