> On 30 Jan 2019, at 09.18, h...@owltronix.com wrote:
> 
> From: Hans Holmberg <hans.holmb...@cnexlabs.com>
> 
> pblk stripes writes of minimal write size across all non-offline chunks
> in a line, which means that the maximum write pointer delta should not
> exceed the minimal write size.
> 
> Extend the line write pointer balance check to cover this case, and
> ignore the offline chunk wps.
> 
> This will render us a warning during recovery if something unexpected
> has happened to the chunk write pointers (i.e. powerloss,  a spurious
> chunk reset, ..).
> 
> Reported-by: Zhoujie Wu <z...@marvell.com>
> Tested-by: Zhoujie Wu <z...@marvell.com>
> Signed-off-by: Hans Holmberg <hans.holmb...@cnexlabs.com>
> ---
> 
> Changes since V1:
> 
>       * Squashed with Zhoujie's:
>        "lightnvm: pblk: ignore bad block wp for pblk_line_wp_is_unbalanced"
>       * Clarified commit message based on Javier's comments.
> 
> 
> drivers/lightnvm/pblk-recovery.c | 56 ++++++++++++++++++++++----------
> 1 file changed, 38 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-recovery.c 
> b/drivers/lightnvm/pblk-recovery.c
> index 6761d2afa4d0..d86f580036d3 100644
> --- a/drivers/lightnvm/pblk-recovery.c
> +++ b/drivers/lightnvm/pblk-recovery.c
> @@ -302,35 +302,55 @@ static int pblk_pad_distance(struct pblk *pblk, struct 
> pblk_line *line)
>       return (distance > line->left_msecs) ? line->left_msecs : distance;
> }
> 
> -static int pblk_line_wp_is_unbalanced(struct pblk *pblk,
> -                                   struct pblk_line *line)
> +/* Return a chunk belonging to a line by stripe(write order) index */
> +static struct nvm_chk_meta *pblk_get_stripe_chunk(struct pblk *pblk,
> +                                               struct pblk_line *line,
> +                                               int index)
> {
>       struct nvm_tgt_dev *dev = pblk->dev;
>       struct nvm_geo *geo = &dev->geo;
> -     struct pblk_line_meta *lm = &pblk->lm;
>       struct pblk_lun *rlun;
> -     struct nvm_chk_meta *chunk;
>       struct ppa_addr ppa;
> -     u64 line_wp;
> -     int pos, i;
> +     int pos;
> 
> -     rlun = &pblk->luns[0];
> +     rlun = &pblk->luns[index];
>       ppa = rlun->bppa;
>       pos = pblk_ppa_to_pos(geo, ppa);
> -     chunk = &line->chks[pos];
> 
> -     line_wp = chunk->wp;
> +     return &line->chks[pos];
> +}
> 
> -     for (i = 1; i < lm->blk_per_line; i++) {
> -             rlun = &pblk->luns[i];
> -             ppa = rlun->bppa;
> -             pos = pblk_ppa_to_pos(geo, ppa);
> -             chunk = &line->chks[pos];
> +static int pblk_line_wps_are_unbalanced(struct pblk *pblk,
> +                                   struct pblk_line *line)
> +{
> +     struct pblk_line_meta *lm = &pblk->lm;
> +     int blk_in_line = lm->blk_per_line;
> +     struct nvm_chk_meta *chunk;
> +     u64 max_wp, min_wp;
> +     int i;
> +
> +     i = find_first_zero_bit(line->blk_bitmap, blk_in_line);
> 
> -             if (chunk->wp > line_wp)
> +     /* If there is one or zero good chunks in the line,
> +      * the write pointers can't be unbalanced.
> +      */
> +     if (i >= (blk_in_line - 1))
> +             return 0;
> +
> +     chunk = pblk_get_stripe_chunk(pblk, line, i);
> +     max_wp = chunk->wp;
> +     if (max_wp > pblk->max_write_pgs)
> +             min_wp = max_wp - pblk->max_write_pgs;
> +     else
> +             min_wp = 0;
> +
> +     i = find_next_zero_bit(line->blk_bitmap, blk_in_line, i + 1);
> +     while (i < blk_in_line) {
> +             chunk = pblk_get_stripe_chunk(pblk, line, i);
> +             if (chunk->wp > max_wp || chunk->wp < min_wp)
>                       return 1;
> -             else if (chunk->wp < line_wp)
> -                     line_wp = chunk->wp;
> +
> +             i = find_next_zero_bit(line->blk_bitmap, blk_in_line, i + 1);
>       }
> 
>       return 0;
> @@ -356,7 +376,7 @@ static int pblk_recov_scan_oob(struct pblk *pblk, struct 
> pblk_line *line,
>       int ret;
>       u64 left_ppas = pblk_sec_in_open_line(pblk, line) - lm->smeta_sec;
> 
> -     if (pblk_line_wp_is_unbalanced(pblk, line))
> +     if (pblk_line_wps_are_unbalanced(pblk, line))
>               pblk_warn(pblk, "recovering unbalanced line (%d)\n", line->id);
> 
>       ppa_list = p.ppa_list;
> --
> 2.17.1

Looks good to me.

Reviewed-by: Javier González <jav...@javigon.com>

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