Re: [PATCH 1/2] btrfs: use correct offset for reloc_inode in prealloc_file_extent_cluster()

[Liu Bo <bo.li.liu@oracle.com>]

On Wed, Jul 06, 2016 at 06:37:52PM +0800, Wang Xiaoguang wrote:
> In prealloc_file_extent_cluster(), btrfs_check_data_free_space() uses
> wrong file offset for reloc_inode, it uses cluster->start and cluster->end,
> which indeed are extent's bytenr. The correct value should be
> cluster->[start|end] minus block group's start bytenr.
> 
> start bytenr   cluster->start
> |              |     extent      |   extent   | ...| extent |
> |----------------------------------------------------------------|
> |                block group reloc_inode                         |
> 
> Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
> ---
>  fs/btrfs/relocation.c | 27 +++++++++++++++------------
>  1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
> index 0477dca..abc2f69 100644
> --- a/fs/btrfs/relocation.c
> +++ b/fs/btrfs/relocation.c
> @@ -3030,34 +3030,37 @@ int prealloc_file_extent_cluster(struct inode *inode,
>  	u64 num_bytes;
>  	int nr = 0;
>  	int ret = 0;
> +	u64 prealloc_start, prealloc_end;
>  
>  	BUG_ON(cluster->start != cluster->boundary[0]);
>  	inode_lock(inode);
>  
> -	ret = btrfs_check_data_free_space(inode, cluster->start,
> -					  cluster->end + 1 - cluster->start);
> +	start = cluster->start - offset;
> +	end = cluster->end - offset;
> +	ret = btrfs_check_data_free_space(inode, start, end + 1 - start);
>  	if (ret)
>  		goto out;
>  
>  	while (nr < cluster->nr) {
> -		start = cluster->boundary[nr] - offset;
> +		prealloc_start = cluster->boundary[nr] - offset;
>  		if (nr + 1 < cluster->nr)
> -			end = cluster->boundary[nr + 1] - 1 - offset;
> +			prealloc_end = cluster->boundary[nr + 1] - 1 - offset;
>  		else
> -			end = cluster->end - offset;
> +			prealloc_end = cluster->end - offset;
>  
> -		lock_extent(&BTRFS_I(inode)->io_tree, start, end);
> -		num_bytes = end + 1 - start;
> -		ret = btrfs_prealloc_file_range(inode, 0, start,
> +		lock_extent(&BTRFS_I(inode)->io_tree, prealloc_start,
> +			    prealloc_end);
> +		num_bytes = prealloc_end + 1 - prealloc_start;
> +		ret = btrfs_prealloc_file_range(inode, 0, prealloc_start,
>  						num_bytes, num_bytes,
> -						end + 1, &alloc_hint);
> -		unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
> +						prealloc_end + 1, &alloc_hint);
> +		unlock_extent(&BTRFS_I(inode)->io_tree, prealloc_start,
> +			      prealloc_end);

Changing names is unnecessary, we can pick up other names for btrfs_{check/free}_data_free_space().

Thanks,

-liubo

>  		if (ret)
>  			break;
>  		nr++;
>  	}
> -	btrfs_free_reserved_data_space(inode, cluster->start,
> -				       cluster->end + 1 - cluster->start);
> +	btrfs_free_reserved_data_space(inode, start, end + 1 - start);
>  out:
>  	inode_unlock(inode);
>  	return ret;
> -- 
> 2.9.0
> 
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html