Re: [PATCH] erofs: don't use erofs_map_blocks() any more

[Gao Xiang <hsiangkao@redhat.com>]

Hi Yue,

On Thu, Mar 25, 2021 at 03:10:08PM +0800, Yue Hu wrote:
> From: Yue Hu <huyue2@yulong.com>
> 
> Currently, erofs_map_blocks() will be called only from
> erofs_{bmap, read_raw_page} which are all for uncompressed files.
> So, the compression branch in erofs_map_blocks() is pointless. Let's
> remove it and use erofs_map_blocks_flatmode() directly. Also update
> related comments.
> 

You are right, since for compressed files, map_blocks_iter would be more
effective than erofs_map_blocks. Originally, such unique interface was
designed for fiemap (just for example), but I'm fine to get rid of it
until related interfaces are finally implemented.

Also, I'd like to hear opinions from Chao as well.

Thanks,
Gao Xiang

> Signed-off-by: Yue Hu <huyue2@yulong.com>
> ---
>  fs/erofs/data.c     | 19 ++-----------------
>  fs/erofs/internal.h |  6 ++----
>  2 files changed, 4 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 1249e74..ebac756 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -109,21 +109,6 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
>  	return err;
>  }
>  
> -int erofs_map_blocks(struct inode *inode,
> -		     struct erofs_map_blocks *map, int flags)
> -{
> -	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
> -		int err = z_erofs_map_blocks_iter(inode, map, flags);
> -
> -		if (map->mpage) {
> -			put_page(map->mpage);
> -			map->mpage = NULL;
> -		}
> -		return err;
> -	}
> -	return erofs_map_blocks_flatmode(inode, map, flags);
> -}
> -
>  static inline struct bio *erofs_read_raw_page(struct bio *bio,
>  					      struct address_space *mapping,
>  					      struct page *page,
> @@ -159,7 +144,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
>  		erofs_blk_t blknr;
>  		unsigned int blkoff;
>  
> -		err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
> +		err = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW);
>  		if (err)
>  			goto err_out;
>  
> @@ -318,7 +303,7 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
>  			return 0;
>  	}
>  
> -	if (!erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW))
> +	if (!erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW))
>  		return erofs_blknr(map.m_pa);
>  
>  	return 0;
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 30e63b7..db8c847 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -289,7 +289,7 @@ static inline unsigned int erofs_inode_datalayout(unsigned int value)
>  extern const struct address_space_operations z_erofs_aops;
>  
>  /*
> - * Logical to physical block mapping, used by erofs_map_blocks()
> + * Logical to physical block mapping
>   *
>   * Different with other file systems, it is used for 2 access modes:
>   *
> @@ -336,7 +336,7 @@ struct erofs_map_blocks {
>  	struct page *mpage;
>  };
>  
> -/* Flags used by erofs_map_blocks() */
> +/* Flags used by erofs_map_blocks_flatmode() */
>  #define EROFS_GET_BLOCKS_RAW    0x0001
>  
>  /* zmap.c */
> @@ -358,8 +358,6 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
>  /* data.c */
>  struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
>  
> -int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
> -
>  /* inode.c */
>  static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
>  {
> -- 
> 1.9.1
>