Re: [PATCH] btrfs: directly wake up cleaner kthread in the BTRFS_IOC_SYNC ioctl

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2024/8/8 03:17, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
>
> The BTRFS_IOC_SYNC ioctl wants to wake up the cleaner kthread so that it
> does any pending work (subvolume deletion, delayed iputs, etc), however
> it is waking up the transaction kthread, which in turn wakes up the
> cleaner. Since we don't have any transaction to commit, as any ongoing
> transaction was already committed when it called btrfs_sync_fs() and
> the goal is just to wake up the cleaner thread, directly wake up the
> cleaner instead of the transaction kthread.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/ioctl.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index e0a664b8a46a..ee01cc828883 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -4765,11 +4765,10 @@ long btrfs_ioctl(struct file *file, unsigned int
>   			return ret;
>   		ret = btrfs_sync_fs(inode->i_sb, 1);
>   		/*
> -		 * The transaction thread may want to do more work,
> -		 * namely it pokes the cleaner kthread that will start
> -		 * processing uncleaned subvols.
> +		 * There may be work for the cleaner kthread to do (subvolume
> +		 * deletion, delayed iputs, defrag inodes, etc), so wake it up.
>   		 */
> -		wake_up_process(fs_info->transaction_kthread);
> +		wake_up_process(fs_info->cleaner_kthread);
>   		return ret;
>   	}
>   	case BTRFS_IOC_START_SYNC: