On 22.08.19 г. 7:17 ч., zhengbin wrote:
> fs/btrfs/raid56.c: In function finish_rmw:
> fs/btrfs/raid56.c:1185:6: warning: variable p_stripe set but not used [-Wunused-but-set-variable]
> fs/btrfs/raid56.c: In function finish_parity_scrub:
> fs/btrfs/raid56.c:2343:6: warning: variable p_stripe set but not used [-Wunused-but-set-variable]
>
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: zhengbin <zhengbin13@xxxxxxxxxx>
Have you tested this patch on a RAID5/6 configuration? WHy do I think
that for the raid 5 case (if (rbio->real_stripes - rbio->nr_data == 1))
we'll now go into the else clause and BUG, despite the variable not
being used.
> ---
> fs/btrfs/raid56.c | 18 ++++--------------
> 1 file changed, 4 insertions(+), 14 deletions(-)
>
> diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> index f3d0576..2603f99 100644
> --- a/fs/btrfs/raid56.c
> +++ b/fs/btrfs/raid56.c
> @@ -1182,7 +1182,6 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
> int nr_data = rbio->nr_data;
> int stripe;
> int pagenr;
> - int p_stripe = -1;
> int q_stripe = -1;
> struct bio_list bio_list;
> struct bio *bio;
> @@ -1190,14 +1189,10 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
>
> bio_list_init(&bio_list);
>
> - if (rbio->real_stripes - rbio->nr_data == 1) {
> - p_stripe = rbio->real_stripes - 1;
> - } else if (rbio->real_stripes - rbio->nr_data == 2) {
> - p_stripe = rbio->real_stripes - 2;
> + if (rbio->real_stripes - rbio->nr_data == 2)
> q_stripe = rbio->real_stripes - 1;
> - } else {
> + else if (rbio->real_stripes - rbio->nr_data != 1)
> BUG();
> - }
>
> /* at this point we either have a full stripe,
> * or we've read the full stripe from the drive.
> @@ -2340,7 +2335,6 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
> int nr_data = rbio->nr_data;
> int stripe;
> int pagenr;
> - int p_stripe = -1;
> int q_stripe = -1;
> struct page *p_page = NULL;
> struct page *q_page = NULL;
> @@ -2351,14 +2345,10 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
>
> bio_list_init(&bio_list);
>
> - if (rbio->real_stripes - rbio->nr_data == 1) {
> - p_stripe = rbio->real_stripes - 1;
> - } else if (rbio->real_stripes - rbio->nr_data == 2) {
> - p_stripe = rbio->real_stripes - 2;
> + if (rbio->real_stripes - rbio->nr_data == 2)
> q_stripe = rbio->real_stripes - 1;
> - } else {
> + else if (rbio->real_stripes - rbio->nr_data != 1)
> BUG();
> - }
>
> if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
> is_replace = 1;
> --
> 2.7.4
>
>
