Re: [PATCH v2 2/2] btrfs: Refactor update_space_info

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

On Wed, May 17, 2017 at 06:07:43PM +0300, Nikolay Borisov wrote:
> Following the factoring out of the creation code udpate_space_info can only
> be called for already-existing space_info structs. Remove superfulous error
> handling and use the return value to return a pointer to the found space_info.
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> Reviewed-by: Jeff Mahoney <jeffm@suse.com>
> ---
>  fs/btrfs/extent-tree.c | 68 ++++++++++++++++++--------------------------------
>  1 file changed, 24 insertions(+), 44 deletions(-)
> 
> Change since v1
>  - Incorporated Jeff Mahoney's feedback and added his reviewed-by tag
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 28848e45b018..3d5bf0b7f719 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -3959,10 +3959,10 @@ static int create_space_info(struct btrfs_fs_info *info, u64 flags,
>  	return ret;
>  }
>  
> -static int update_space_info(struct btrfs_fs_info *info, u64 flags,
> -			     u64 total_bytes, u64 bytes_used,
> -			     u64 bytes_readonly,
> -			     struct btrfs_space_info **space_info)
> +static struct btrfs_space_info *update_space_info(struct btrfs_fs_info *info,
> +												 u64 flags, u64 total_bytes,
> +												 u64 bytes_used,
> +												 u64 bytes_readonly)

The format shown here is not indented correctly.  Please check the tool you
generated the patch or the email client.

I remember that your previous patch set about converting struct inode to struct
btrfs_inode also breaks several indent in code.

>  {
>  	struct btrfs_space_info *found;
>  	int factor;
> @@ -3974,21 +3974,21 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
>  		factor = 1;
>  
>  	found = __find_space_info(info, flags);
> -	if (found) {
> -		spin_lock(&found->lock);
> -		found->total_bytes += total_bytes;
> -		found->disk_total += total_bytes * factor;
> -		found->bytes_used += bytes_used;
> -		found->disk_used += bytes_used * factor;
> -		found->bytes_readonly += bytes_readonly;
> -		if (total_bytes > 0)
> -			found->full = 0;
> -		space_info_add_new_bytes(info, found, total_bytes -
> -					 bytes_used - bytes_readonly);
> -		spin_unlock(&found->lock);
> -		*space_info = found;
> -		return 0;
> -	}
> +	BUG_ON(!found);

No more BUG_ON(), try ASSERT for debugging purpose.

> +
> +	spin_lock(&found->lock);
> +	found->total_bytes += total_bytes;
> +	found->disk_total += total_bytes * factor;
> +	found->bytes_used += bytes_used;
> +	found->disk_used += bytes_used * factor;
> +	found->bytes_readonly += bytes_readonly;
> +	if (total_bytes > 0)
> +		found->full = 0;
> +	space_info_add_new_bytes(info, found, total_bytes -
> +				 bytes_used - bytes_readonly);
> +	spin_unlock(&found->lock);
> +
> +	return found;
>  }
>  
>  static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
> @@ -10042,19 +10042,9 @@ int btrfs_read_block_groups(struct btrfs_fs_info *info)
>  		}
>  
>  		trace_btrfs_add_block_group(info, cache, 0);
> -		ret = update_space_info(info, cache->flags, found_key.offset,
> -					btrfs_block_group_used(&cache->item),
> -					cache->bytes_super, &space_info);
> -		if (ret) {
> -			btrfs_remove_free_space_cache(cache);
> -			spin_lock(&info->block_group_cache_lock);
> -			rb_erase(&cache->cache_node,
> -				 &info->block_group_cache_tree);
> -			RB_CLEAR_NODE(&cache->cache_node);
> -			spin_unlock(&info->block_group_cache_lock);
> -			btrfs_put_block_group(cache);
> -			goto error;
> -		}
> +		space_info = update_space_info(info, cache->flags, found_key.offset,
> +									  btrfs_block_group_used(&cache->item),
> +									  cache->bytes_super);
>

Same indent issue.

>  		cache->space_info = space_info;
>  
> @@ -10212,18 +10202,8 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
>  	 * the rbtree, update the space info's counters.
>  	 */
>  	trace_btrfs_add_block_group(fs_info, cache, 1);
> -	ret = update_space_info(fs_info, cache->flags, size, bytes_used,
> -				cache->bytes_super, &cache->space_info);
> -	if (ret) {
> -		btrfs_remove_free_space_cache(cache);
> -		spin_lock(&fs_info->block_group_cache_lock);
> -		rb_erase(&cache->cache_node,
> -			 &fs_info->block_group_cache_tree);
> -		RB_CLEAR_NODE(&cache->cache_node);
> -		spin_unlock(&fs_info->block_group_cache_lock);
> -		btrfs_put_block_group(cache);
> -		return ret;
> -	}
> +	cache->space_info = update_space_info(fs_info, cache->flags, size,
> +										 bytes_used, cache->bytes_super);

Same indent issue.

Thanks,

-liubo
>  	update_global_block_rsv(fs_info);
>  
>  	__link_block_group(cache->space_info, cache);
> -- 
> 2.7.4
> 
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