diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 92c44ed..d96305e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1976,6 +1976,7 @@
 	btrfs_stop_workers(&fs_info->caching_workers);
 	btrfs_stop_workers(&fs_info->readahead_workers);
 	btrfs_stop_workers(&fs_info->flush_workers);
+	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
 }
 
 /* helper to cleanup tree roots */
@@ -2267,6 +2268,7 @@
 	fs_info->qgroup_seq = 1;
 	fs_info->quota_enabled = 0;
 	fs_info->pending_quota_state = 0;
+	mutex_init(&fs_info->qgroup_rescan_lock);
 
 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
@@ -2476,6 +2478,8 @@
 	btrfs_init_workers(&fs_info->readahead_workers, "readahead",
 			   fs_info->thread_pool_size,
 			   &fs_info->generic_worker);
+	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
+			   &fs_info->generic_worker);
 
 	/*
 	 * endios are largely parallel and should have a very
@@ -2510,6 +2514,7 @@
 	ret |= btrfs_start_workers(&fs_info->caching_workers);
 	ret |= btrfs_start_workers(&fs_info->readahead_workers);
 	ret |= btrfs_start_workers(&fs_info->flush_workers);
+	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;