On Wed, Mar 20, 2019 at 02:27:41PM +0800, Qu Wenruo wrote:
> We have a BUG_ON() in flush_write_bio() to handle the return value of
> submit_one_bio().
>
> Move the BUG_ON() one level up to all its callers.
>
> This patch will introduce temporary variable, @flush_ret to keep code
> change minimal in this patch. That variable will be cleaned up when
> enhancing the error handling later.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> ---
> fs/btrfs/extent_io.c | 55 +++++++++++++++++++++++++++++++++-----------
> 1 file changed, 41 insertions(+), 14 deletions(-)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index ca8b8e785cf3..58bf6ae29319 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -170,15 +170,28 @@ static int __must_check submit_one_bio(struct bio *bio, int mirror_num,
> return blk_status_to_errno(ret);
> }
>
> -static void flush_write_bio(struct extent_page_data *epd)
> +/*
> + * A wrapper for submit_one_bio().
Such comments are not very useful, changed to "Submit bio from extent
page data via submit_one_bio".
> + *
> + * Return 0 if everything is OK.
> + * Return <0 for error.
> + */
> +static int __must_check flush_write_bio(struct extent_page_data *epd)
> {
> - if (epd->bio) {
> - int ret;
> + int ret = 0;
>
> + if (epd->bio) {
> ret = submit_one_bio(epd->bio, 0, 0);
> - BUG_ON(ret < 0); /* -ENOMEM */
> + /*
> + * Clean up of epd->bio is handled by its endio function.
> + * And endio is either triggered by successful bio execution
> + * or the error handler of submit bio hook.
> + * So at this point, no matter what happened, we don't need
> + * to clean up epd->bio.
> + */
That one is great.
