Commit 3b7a016f authored by Wang Shilong's avatar Wang Shilong Committed by Chris Mason
Browse files

Btrfs: avoid unnecessary scrub workers allocation 



We only allocate scrub workers if we pass all the necessary
checks, for example, there are no operation in progress.

Besides, move mutex lock protection outside of scrub_workers_get()
/scrub_workers_put().

Signed-off-by: default avatarWang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@fusionio.com>
parent 007d31f7

fs/btrfs/scrub.c

+10 −13
Original line number Diff line number Diff line
@@ -2784,7 +2784,6 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info, 
{

	int ret = 0;



	mutex_lock(&fs_info->scrub_lock);

	if (fs_info->scrub_workers_refcnt == 0) {

		if (is_dev_replace)

			btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
@@ -2814,21 +2813,17 @@ static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info, 
	}

	++fs_info->scrub_workers_refcnt;

out:

	mutex_unlock(&fs_info->scrub_lock);



	return ret;

}



static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)

{

	mutex_lock(&fs_info->scrub_lock);

	if (--fs_info->scrub_workers_refcnt == 0) {

		btrfs_stop_workers(&fs_info->scrub_workers);

		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);

		btrfs_stop_workers(&fs_info->scrub_nocow_workers);

	}

	WARN_ON(fs_info->scrub_workers_refcnt < 0);

	mutex_unlock(&fs_info->scrub_lock);

}



int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
@@ -2889,23 +2884,18 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 
		return -EINVAL;

	}



	ret = scrub_workers_get(fs_info, is_dev_replace);

	if (ret)

		return ret;



	mutex_lock(&fs_info->fs_devices->device_list_mutex);

	dev = btrfs_find_device(fs_info, devid, NULL, NULL);

	if (!dev || (dev->missing && !is_dev_replace)) {

		mutex_unlock(&fs_info->fs_devices->device_list_mutex);

		scrub_workers_put(fs_info);

		return -ENODEV;

	}

	mutex_lock(&fs_info->scrub_lock);



	mutex_lock(&fs_info->scrub_lock);

	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {

		mutex_unlock(&fs_info->scrub_lock);

		mutex_unlock(&fs_info->fs_devices->device_list_mutex);

		scrub_workers_put(fs_info);

		return -EIO;

	}
@@ -2916,10 +2906,17 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 
		btrfs_dev_replace_unlock(&fs_info->dev_replace);

		mutex_unlock(&fs_info->scrub_lock);

		mutex_unlock(&fs_info->fs_devices->device_list_mutex);

		scrub_workers_put(fs_info);

		return -EINPROGRESS;

	}

	btrfs_dev_replace_unlock(&fs_info->dev_replace);



	ret = scrub_workers_get(fs_info, is_dev_replace);

	if (ret) {

		mutex_unlock(&fs_info->scrub_lock);

		mutex_unlock(&fs_info->fs_devices->device_list_mutex);

		return ret;

	}



	sctx = scrub_setup_ctx(dev, is_dev_replace);

	if (IS_ERR(sctx)) {

		mutex_unlock(&fs_info->scrub_lock);
@@ -2957,10 +2954,10 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, 


	mutex_lock(&fs_info->scrub_lock);

	dev->scrub_device = NULL;

	scrub_workers_put(fs_info);

	mutex_unlock(&fs_info->scrub_lock);



	scrub_free_ctx(sctx);

	scrub_workers_put(fs_info);



	return ret;

}