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

From: Andrew Morton
Date: Mon Oct 25 2010 - 19:11:54 EST


On Sun, 24 Oct 2010 01:11:54 +0900
Namhyung Kim <namhyung@xxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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)
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