RE: [PATCH v2] Btrfs: remove unnecessary code of chunk_root assignment in btrfs_read_chunk_tree.

[Zhao Lei <zhaolei@cn.fujitsu.com>]

Hi, Sean Fu

> -----Original Message-----
> From: Sean Fu [mailto:fxinrong@gmail.com]
> Sent: Tuesday, September 06, 2016 11:51 AM
> To: dsterba@suse.com
> Cc: clm@fb.com; anand.jain@oracle.com; fdmanana@suse.com;
> zhaolei@cn.fujitsu.com; linux-kernel@vger.kernel.org;
> linux-btrfs@vger.kernel.org; Sean Fu <fxinrong@gmail.com>
> Subject: [PATCH v2] Btrfs: remove unnecessary code of chunk_root assignment
> in btrfs_read_chunk_tree.
> 
> The input argument root is already set with "fs_info->chunk_root".
> "chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info)" in caller
> "open_ctree".
> "root->fs_info = fs_info” in "btrfs_alloc_root".
> 
> Signed-off-by: Sean Fu <fxinrong@gmail.com>
> ---
> Changes in v2:
>   - Renaming root to chunk_root to make it clear.
> 
>  fs/btrfs/volumes.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 366b335..eb3d04a 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -6591,7 +6591,7 @@ out_short_read:
>  	return -EIO;
>  }
> 
> -int btrfs_read_chunk_tree(struct btrfs_root *root)
> +int btrfs_read_chunk_tree(struct btrfs_root *chunk_root)

Maybe you also need to modify function body to make it
pass compile, and the header file also need to be modified.

BTW, Qu Wenruo give us a better way in reply, we
can use fs_info directly.

Thanks
Zhaolei

>  {
>  	struct btrfs_path *path;
>  	struct extent_buffer *leaf;
> @@ -6600,8 +6600,6 @@ int btrfs_read_chunk_tree(struct btrfs_root *root)
>  	int ret;
>  	int slot;
> 
> -	root = root->fs_info->chunk_root;
> -
>  	path = btrfs_alloc_path();
>  	if (!path)
>  		return -ENOMEM;
> --
> 2.6.2
>