Re: [PATCH 2/7] ext4: tell DAX the size of allocation holes

[Jan Kara]

On Mon 15-08-16 13:09:13, Ross Zwisler wrote:
> When DAX calls _ext4_get_block() and the file offset points to a hole we
> currently don't set bh->b_size.  When we re-enable PMD faults DAX will
> need bh->b_size to tell it the size of the hole so it can decide whether to
> fault in a 4 KiB zero page or a 2 MiB zero page.
> 
> _ext4_get_block() has the hole size information from ext4_map_blocks(), so
> populate bh->b_size.
> 
> Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  fs/ext4/inode.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 3131747..1808013 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -759,6 +759,9 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock,
>  		ext4_update_bh_state(bh, map.m_flags);
>  		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
>  		ret = 0;
> +	} else if (ret == 0) {
> +		/* hole case, need to fill in bh->b_size */
> +		bh->b_size = inode->i_sb->s_blocksize * map.m_len;
>  	}
>  	return ret;
>  }
> -- 
> 2.9.0
> 
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR