btrfs: Replace fs_info->qgroup_rescan_worker workqueue with btrfs_workqueue.

Replace the fs_info->qgroup_rescan_worker with the newly created
btrfs_workqueue.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Tested-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>

fs/btrfs/ctree.h

@@ -1648,9 +1648,9 @@ struct btrfs_fs_info {
 	/* qgroup rescan items */
 	struct mutex qgroup_rescan_lock; /* protects the progress item */
 	struct btrfs_key qgroup_rescan_progress;
-	struct btrfs_workers qgroup_rescan_workers;
+	struct btrfs_workqueue_struct *qgroup_rescan_workers;
 	struct completion qgroup_rescan_completion;
-	struct btrfs_work qgroup_rescan_work;
+	struct btrfs_work_struct qgroup_rescan_work;
 
 	/* filesystem state */
 	unsigned long fs_state;

fs/btrfs/disk-io.c

@@ -2010,7 +2010,7 @@ static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
 	btrfs_destroy_workqueue(fs_info->caching_workers);
 	btrfs_destroy_workqueue(fs_info->readahead_workers);
 	btrfs_destroy_workqueue(fs_info->flush_workers);
-	btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
+	btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
 }
 
 static void free_root_extent_buffers(struct btrfs_root *root)
@@ -2523,15 +2523,14 @@ int open_ctree(struct super_block *sb,
 		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
 	fs_info->readahead_workers =
 		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
-	btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
-			   &fs_info->generic_worker);
+	fs_info->qgroup_rescan_workers =
+		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
 
 	/*
 	 * btrfs_start_workers can really only fail because of ENOMEM so just
 	 * return -ENOMEM if any of these fail.
 	 */
 	ret = btrfs_start_workers(&fs_info->generic_worker);
-	ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
 	if (ret) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
@@ -2543,7 +2542,8 @@ int open_ctree(struct super_block *sb,
 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
 	      fs_info->caching_workers && fs_info->readahead_workers &&
-	      fs_info->fixup_workers && fs_info->delayed_workers)) {
+	      fs_info->fixup_workers && fs_info->delayed_workers &&
+	      fs_info->qgroup_rescan_workers)) {
 		err = -ENOMEM;
 		goto fail_sb_buffer;
 	}

fs/btrfs/qgroup.c

@@ -1509,8 +1509,8 @@ int btrfs_run_qgroups(struct btrfs_trans_handle *trans,
 		ret = qgroup_rescan_init(fs_info, 0, 1);
 		if (!ret) {
 			qgroup_rescan_zero_tracking(fs_info);
-			btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-					   &fs_info->qgroup_rescan_work);
+			btrfs_queue_work(fs_info->qgroup_rescan_workers,
+					 &fs_info->qgroup_rescan_work);
 		}
 		ret = 0;
 	}
@@ -1984,7 +1984,7 @@ qgroup_rescan_leaf(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
 	return ret;
 }
 
-static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
+static void btrfs_qgroup_rescan_worker(struct btrfs_work_struct *work)
 {
 	struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
 						     qgroup_rescan_work);
@@ -2095,7 +2095,8 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
 
 	memset(&fs_info->qgroup_rescan_work, 0,
 	       sizeof(fs_info->qgroup_rescan_work));
-	fs_info->qgroup_rescan_work.func = btrfs_qgroup_rescan_worker;
+	btrfs_init_work(&fs_info->qgroup_rescan_work,
+			btrfs_qgroup_rescan_worker, NULL, NULL);
 
 	if (ret) {
 err:
@@ -2158,8 +2159,8 @@ btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
 
 	qgroup_rescan_zero_tracking(fs_info);
 
-	btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-			   &fs_info->qgroup_rescan_work);
+	btrfs_queue_work(fs_info->qgroup_rescan_workers,
+			 &fs_info->qgroup_rescan_work);
 
 	return 0;
 }
@@ -2190,6 +2191,6 @@ void
 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
 {
 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
-		btrfs_queue_worker(&fs_info->qgroup_rescan_workers,
-				   &fs_info->qgroup_rescan_work);
+		btrfs_queue_work(fs_info->qgroup_rescan_workers,
+				 &fs_info->qgroup_rescan_work);
 }