Re: [patch 14/19] Use page_cache_xxx in ext2

[David Chinner <dgc@sgi.com>]

On Wed, Nov 28, 2007 at 07:55:40PM -0800, Christoph Lameter wrote:
> ext2: Simplify some functions
> 
> Signed-off-by: Christoph Lameter <clameter@sgi.com>
> 
> ---
>  fs/ext2/dir.c |    9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> Index: mm/fs/ext2/dir.c
> ===================================================================
> --- mm.orig/fs/ext2/dir.c	2007-11-28 19:51:05.038882954 -0800
> +++ mm/fs/ext2/dir.c	2007-11-28 19:53:59.074132710 -0800
> @@ -63,8 +63,7 @@ static inline void ext2_put_page(struct 
>  
>  static inline unsigned long dir_pages(struct inode *inode)
>  {
> -	return (inode->i_size+page_cache_size(inode->i_mapping)-1)>>
> -			page_cache_shift(inode->i_mapping);
> +	return page_cache_next(inode->i_mapping, inode->i_size);
>  }

ok.

>  /*
> @@ -74,13 +73,9 @@ static inline unsigned long dir_pages(st
>  static unsigned
>  ext2_last_byte(struct inode *inode, unsigned long page_nr)
>  {
> -	unsigned last_byte = inode->i_size;
>  	struct address_space *mapping = inode->i_mapping;
>  
> -	last_byte -= page_nr << page_cache_shift(mapping);
> -	if (last_byte > page_cache_size(mapping))
> -		last_byte = page_cache_size(mapping);
> -	return last_byte;
> +	return inode->i_size - page_cache_pos(mapping, page_nr, 0);

I don't think that gives the same return value. The return value
is supposed to be clamped at a maximum of page_cache_size(mapping).

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group