Re: [PATCH 02/10] ext4: ext4_block_truncate_page() returns zeroed length on success

[Jan Kara]

On Tue 10-03-26 09:40:53, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@xxxxxxxxxx>
> 
> Return the actual zeroed length instead of 0 on success. This prepares
> for the upcoming iomap buffered I/O conversion by exposing zeroed length
> information to callers.
> 
> Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
>  fs/ext4/inode.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 1e037a314dab..a737ce05e768 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -4136,6 +4136,7 @@ static int ext4_block_zero_page_range(handle_t *handle,
>   * up to the end of the block which corresponds to `from'.
>   * This required during truncate. We need to physically zero the tail end
>   * of that block so it doesn't yield old data if the file is later grown.
> + * Return the zeroed length on success.
>   */
>  static int ext4_block_truncate_page(handle_t *handle,
>  		struct address_space *mapping, loff_t from)
> @@ -4143,6 +4144,8 @@ static int ext4_block_truncate_page(handle_t *handle,
>  	unsigned length;
>  	unsigned blocksize;
>  	struct inode *inode = mapping->host;
> +	bool did_zero = false;
> +	int err;
>  
>  	/* If we are processing an encrypted inode during orphan list handling */
>  	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
> @@ -4151,7 +4154,12 @@ static int ext4_block_truncate_page(handle_t *handle,
>  	blocksize = i_blocksize(inode);
>  	length = blocksize - (from & (blocksize - 1));
>  
> -	return ext4_block_zero_page_range(handle, mapping, from, length, NULL);
> +	err = ext4_block_zero_page_range(handle, mapping, from, length,
> +					 &did_zero);
> +	if (err)
> +		return err;
> +
> +	return did_zero ? length : 0;
>  }
>  
>  int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
> -- 
> 2.52.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR