Re: [PATCH v2 14/16] lightnvm: pblk: GC error handling

[Matias Bjørling <mb@xxxxxxxxxxx>]

On 3/22/19 3:48 PM, Igor Konopko wrote:
> Currently when there is an IO error (or similar) on GC read path, pblk
> still moves this line to free state

What those "this" line refer to?

, what leads to data mismatch issue.

what -> which leads to a data mismatch.
> This patch adds a handling for such an error - after that changes this
> line will be returned to closed state so it can be still in use
> for reading - at least we will be able to return error status to user
> when user tries to read such a data.

Could you update the description. It is hard for me to parse.

> Signed-off-by: Igor Konopko <igor.j.konopko@xxxxxxxxx>
> Reviewed-by: Javier González <javier@xxxxxxxxxxx>
> Reviewed-by: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
> ---
>   drivers/lightnvm/pblk-core.c | 8 ++++++++
>   drivers/lightnvm/pblk-gc.c   | 5 ++---
>   drivers/lightnvm/pblk-read.c | 1 -
>   drivers/lightnvm/pblk.h      | 2 ++
>   4 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 9d9a9e2..1b88e5e 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -1799,6 +1799,14 @@ static void __pblk_line_put(struct pblk *pblk, struct pblk_line *line)
>   
>   	spin_lock(&line->lock);
>   	WARN_ON(line->state != PBLK_LINESTATE_GC);
> +	if (line->w_err_gc->has_gc_err) {
> +		spin_unlock(&line->lock);
> +		pblk_err(pblk, "line %d had errors during GC\n", line->id);
> +		pblk_put_line_back(pblk, line);
> +		line->w_err_gc->has_gc_err = 0;
> +		return;
> +	}
> +
>   	line->state = PBLK_LINESTATE_FREE;
>   	trace_pblk_line_state(pblk_disk_name(pblk), line->id,
>   					line->state);
> diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c
> index e23b192..63ee205 100644
> --- a/drivers/lightnvm/pblk-gc.c
> +++ b/drivers/lightnvm/pblk-gc.c
> @@ -59,7 +59,7 @@ static void pblk_gc_writer_kick(struct pblk_gc *gc)
>   	wake_up_process(gc->gc_writer_ts);
>   }
>   
> -static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
> +void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
>   {
>   	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
>   	struct list_head *move_list;
> @@ -98,8 +98,7 @@ static void pblk_gc_line_ws(struct work_struct *work)
>   	/* Read from GC victim block */
>   	ret = pblk_submit_read_gc(pblk, gc_rq);
>   	if (ret) {
> -		pblk_err(pblk, "failed GC read in line:%d (err:%d)\n",
> -								line->id, ret);
> +		line->w_err_gc->has_gc_err = 1;
>   		goto out;
>   	}
>   
> diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
> index 264d1d7..5481dfa 100644
> --- a/drivers/lightnvm/pblk-read.c
> +++ b/drivers/lightnvm/pblk-read.c
> @@ -494,7 +494,6 @@ int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
>   
>   	if (pblk_submit_io_sync(pblk, &rqd)) {
>   		ret = -EIO;
> -		pblk_err(pblk, "GC read request failed\n");
>   		goto err_free_bio;
>   	}
>   
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index 0999245..0bc4255 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -425,6 +425,7 @@ struct pblk_smeta {
>   
>   struct pblk_w_err_gc {
>   	int has_write_err;
> +	int has_gc_err;
>   	__le64 *lba_list;
>   };
>   
> @@ -916,6 +917,7 @@ void pblk_gc_free_full_lines(struct pblk *pblk);
>   void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
>   			      int *gc_active);
>   int pblk_gc_sysfs_force(struct pblk *pblk, int force);
> +void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line);
>   
>   /*
>    * pblk rate limiter