Re: [PATCH UPDATED] fs/buffer.c: call __block_write_begin() if we have page

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 24 Oct 2010 01:11:54 +0900
Namhyung Kim <namhyung@gmail.com> wrote:

> If we have the appropriate page already, call __block_write_begin()
> directly instead of releasing and regrabbing it inside of
> block_write_begin().
> 
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>
> ---
> Fix error path.
> 
>  fs/buffer.c |   12 +++++++-----
>  1 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/buffer.c b/fs/buffer.c
> index 7f0b9b0..f5755f7 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -2466,11 +2466,13 @@ int nobh_write_begin(struct address_space *mapping,
>  	*fsdata = NULL;
>  
>  	if (page_has_buffers(page)) {
> -		unlock_page(page);
> -		page_cache_release(page);
> -		*pagep = NULL;
> -		return block_write_begin(mapping, pos, len, flags, pagep,
> -					 get_block);
> +		ret = __block_write_begin(page, pos, len, get_block);
> +		if (unlikely(ret)) {
> +			unlock_page(page);
> +			page_cache_release(page);
> +			*pagep = NULL;
> +		}
> +		return ret;
>  	}
>  
>  	if (PageMappedToDisk(page))

It looks OK.  Was it tested?  (ext2 mounted with -o nobh)