Re: [PATCH 4/5] f2fs: support data flush in ioctl

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hi Chao,

On Thu, Dec 24, 2015 at 06:10:25PM +0800, Chao Yu wrote:
> Sometimes user want to sync all data belong to superblock into storage
> for persistence, 'syncfs' syscall is one option, still f2fs supports
> similar one through ioctl, difference is that sb releted kworker is
> online for writebacking concurrently.

There is compatibility issue, since you're trying to change pre-defined
ioctl; it needs to change F2FS_IOC_WRITE_CHECKPOINT too, right?
I'm in doubt that we really need to expose this too.

Thanks,

> 
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/file.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index a60d088..91997a5 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1621,6 +1621,7 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>  	struct cp_control cpc;
>  	int err;
> +	int flush_data;
>  
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> @@ -1628,6 +1629,15 @@ static int f2fs_ioc_write_checkpoint(struct file *filp, unsigned long arg)
>  	if (f2fs_readonly(sbi->sb))
>  		return -EROFS;
>  
> +	if (get_user(flush_data, (__u32 __user *)arg))
> +		return -EFAULT;
> +
> +	if (flush_data) {
> +		err = sync_dirty_inodes(sbi, FILE_INODE);
> +		if (err)
> +			return err;
> +	}
> +
>  	cpc.reason = __get_cp_reason(sbi);
>  
>  	mutex_lock(&sbi->gc_mutex);
> -- 
> 2.6.3
>