diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c9ab67d..493370e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -958,6 +958,7 @@
 	INIT_LIST_HEAD(&ei->i_orphan);
 	init_rwsem(&ei->xattr_sem);
 	init_rwsem(&ei->i_data_sem);
+	init_rwsem(&ei->i_mmap_sem);
 	inode_init_once(&ei->vfs_inode);
 }