Re: [RFC PATCH v4 27/34] ext4: implement zero_range iomap path

[Dave Chinner]

On Wed, Apr 10, 2024 at 10:29:41PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
> 
> Add ext4_iomap_zero_range() for the zero_range iomap path, it zero out
> the mapped blocks, all work have been done in iomap_zero_range(), so
> call it directly.
> 
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
> ---
>  fs/ext4/inode.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 9d694c780007..5af3b8acf1b9 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4144,6 +4144,13 @@ static int __ext4_block_zero_page_range(handle_t *handle,
>  	return err;
>  }
>  
> +static int ext4_iomap_zero_range(struct inode *inode,
> +				 loff_t from, loff_t length)
> +{
> +	return iomap_zero_range(inode, from, length, NULL,
> +				&ext4_iomap_buffered_read_ops);
> +}

Zeroing is a buffered write operation, not a buffered read
operation. It runs though iomap_write_begin(), so needs all the
stale iomap detection stuff to be set up for correct operation.

-Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx