Re: [PATCH 4/4] fsx: move range generation logic into a common helper

[Brian Foster <bfoster@redhat.com>]

On Mon, Apr 20, 2020 at 06:09:31PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> We have very similar code that generates the destination range for clone,
> dedupe and copy_file_range operations, so avoid duplicating the code three
> times and move it into a helper function.
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  ltp/fsx.c | 94 ++++++++++++++++++++++++++-------------------------------------
>  1 file changed, 39 insertions(+), 55 deletions(-)
> 
> diff --git a/ltp/fsx.c b/ltp/fsx.c
> index 40cbd401..7c76655a 100644
> --- a/ltp/fsx.c
> +++ b/ltp/fsx.c
> @@ -1939,6 +1939,39 @@ range_overlaps(
>  	return llabs((unsigned long long)off1 - off0) < size;
>  }
>  
> +static void generate_dest_range(bool bdy_align,
> +				unsigned long max_range_end,
> +				unsigned long *src_offset,
> +				unsigned long *size,
> +				unsigned long *dst_offset)
> +{
> +	int tries = 0;
> +
> +	TRIM_OFF_LEN(*src_offset, *size, file_size);
> +	if (bdy_align) {
> +		*src_offset -= *src_offset % readbdy;
> +		if (o_direct)
> +			*size -= *size % readbdy;
> +	} else {
> +		*src_offset = *src_offset & ~(block_size - 1);
> +		*size = *size & ~(block_size - 1);
> +	}
> +
> +	do {
> +		if (tries++ >= 30) {
> +			*size = 0;
> +			break;
> +		}
> +		*dst_offset = random();
> +		TRIM_OFF(*dst_offset, max_range_end);
> +		if (bdy_align)
> +			*dst_offset -= *dst_offset % writebdy;
> +		else
> +			*dst_offset = *dst_offset & ~(block_size - 1);
> +	} while (range_overlaps(*src_offset, *dst_offset, *size) ||
> +		 *dst_offset + *size > max_range_end);
> +}
> +
>  int
>  test(void)
>  {
> @@ -2013,63 +2046,14 @@ test(void)
>  			keep_size = random() % 2;
>  		break;
>  	case OP_CLONE_RANGE:
> -		{
> -			int tries = 0;
> -
> -			TRIM_OFF_LEN(offset, size, file_size);
> -			offset = offset & ~(block_size - 1);
> -			size = size & ~(block_size - 1);
> -			do {
> -				if (tries++ >= 30) {
> -					size = 0;
> -					break;
> -				}
> -				offset2 = random();
> -				TRIM_OFF(offset2, maxfilelen);
> -				offset2 = offset2 & ~(block_size - 1);
> -			} while (range_overlaps(offset, offset2, size) ||
> -				 offset2 + size > maxfilelen);
> -			break;
> -		}
> +		generate_dest_range(false, maxfilelen, &offset, &size, &offset2);
> +		break;
>  	case OP_DEDUPE_RANGE:
> -		{
> -			int tries = 0;
> -
> -			TRIM_OFF_LEN(offset, size, file_size);
> -			offset = offset & ~(block_size - 1);
> -			size = size & ~(block_size - 1);
> -			do {
> -				if (tries++ >= 30) {
> -					size = 0;
> -					break;
> -				}
> -				offset2 = random();
> -				TRIM_OFF(offset2, file_size);
> -				offset2 = offset2 & ~(block_size - 1);
> -			} while (range_overlaps(offset, offset2, size) ||
> -				 offset2 + size > file_size);
> -			break;
> -		}
> +		generate_dest_range(false, file_size, &offset, &size, &offset2);
> +		break;
>  	case OP_COPY_RANGE:
> -		{
> -			int tries = 0;
> -
> -			TRIM_OFF_LEN(offset, size, file_size);
> -			offset -= offset % readbdy;
> -			if (o_direct)
> -				size -= size % readbdy;
> -			do {
> -				if (tries++ >= 30) {
> -					size = 0;
> -					break;
> -				}
> -				offset2 = random();
> -				TRIM_OFF(offset2, maxfilelen);
> -				offset2 -= offset2 % writebdy;
> -			} while (range_overlaps(offset, offset2, size) ||
> -				 offset2 + size > maxfilelen);
> -			break;
> -		}
> +		generate_dest_range(true, maxfilelen, &offset, &size, &offset2);
> +		break;
>  	}
>  
>  have_op:
> -- 
> 2.11.0
>