Re: Approach to quickly zeroing large XFS file (or) tool to mark XFS file extents as written

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Dec 23, 2024 at 10:12:32PM +0530, Sai Chaitanya Mitta wrote:
> Hi Team,
>            Is there any method/tool available to explicitly mark XFS
> file extents as written? One approach I
> am aware is explicitly zeroing the entire file (this file may be even
> in hundreds of GB in size) through
> synchronous/asynchronous(aio/io_uring) mechanism but it is time taking
> process for large files,
> is there any optimization/approach we can do to explicitly zeroing
> file/mark extents as written?

Why do you need to mark them written?

--D

> 
> Synchronous Approach:
>                     while offset < size {
>                         let bytes_written = img_file
>                             .write_at(&buf, offset)
>                             .map_err(|e| {
>                                 error!("Failed to zero out file: {}
> error: {:?}", vol_name, e);
>                             })?;
>                         if offset == size {
>                             break;
>                         }
>                         offset = offset + bytes_written as u64;
>                     }
>                     img_file.sync_all();
> 
> Asynchronous approach:
>                    Currently used fio with libaio as ioengine but
> results are almost same.
> 
> -- 
> Thanks& Regards,
> M.Sai Chaithanya.
>